International Journal of Conservation Science

IJCS homepage

Print ISSN:   2067-533X
Online ISSN: 2067-8223
Journal Information

For Readers

For Authors

For Reviewers


Current Issue

Volume 8, Issue 3, 2017

         Table of contents  

Click for Cover

Issue Cover

Research articles

L. Pereira-Pardo, B. Prieto, B. Silva

Assessing The Risk of Salt Decay for Wall Paintings in Historic Buildings. Thermo-dynamic Modeling and Transition Cycles Count

[ Abstract ]
[ Full Article - PDF ]                  pp. 351-364

Salt crystallisation is a major cause of deterioration of porous building materials, strongly related to the fluctuation of the environmental parameters. This paper explores the application of different methodologies to assess the potential damage caused by soluble salts to a series of sixteenth century frescoes with the thermo-hygrometric variations. The method of counting the transition cycles for six crystalline systems, the thermodynamic model ECOS for mixed salt solutions and a combination of both methodologies were used, in order to evaluate and compare these different approaches and to determine the risk of salt decay for this particularly sensitive case study. To this end, the temperature and relative humidity in the churches housing the wall paintings were monitored during a year and the salt content of the frescoes analysed. The seasonality of the salt crystallisation was studied and the range of relative humidity at which the transitions occurred determined. All methods identified a significant risk of salt decay, mainly related to the crystallisation of chlorides and nitrates, which corresponds well with the observations in situ. Finally, the advantages and inconveniences of each method were discussed, along with the results obtained in other published works, and the combined method was suggested as the most efficient

Keywords: Salt weathering; Risk assessment; Environmental monitoring; Wall paintings; ECOS; Transition cycles count

F. Gao, Y. Qi, W. Zhou, S. Liu

Evaluation and Formation Mechanism of Surface Contaminants and Stratification on the Rock Paintings of Huashan Mountain (Guangxi, China)

[ Abstract ]
[ Full Article - PDF]                  pp. 365-374
The Rock Paintings of Huashan Mountain dated back from ~1620 to ~4800 years ago provide clear and definite information on the history of ancient Luoyue people. Investigation shows that a great amount of water drops attached to the rock surface combining with dusts resulted in the formation of mud wrapping layers covering the rock paintings. Yellow thick and dense calcium based stratification on the limestone due to the karst water seepage are very commonly observed as well. Both are main factors that are ascribed to the spallation of the rock painting from the limestones. Combining with on-site and laboratory measurements using SEM with EDS, X-ray diffraction, portable XPS, and stereoscopic microscopy, this work aims to characterize the mud wrappings and dense calcium based stratification on the surface of the rock painting and clarify the underlying mechanisms that cause a large scale of spallation on the rock paintings, a phenomenon that has to be resolved or retarded urgently. This work allows the execution of specifically directed conservation strategies and chooses the most appropriate cleaning technique. Especially, it has provided a solid technological support to the restoration project conducted from 2010 to 2013.

Keywords: Cultural heritage; Limestone monuments; Rock paintings; Surface stratifications

I.C. Nicu

Natural Hazards – A Threat for Immovable Cultural Heritage. A Review

[ Abstract ]
[ Full Article - PDF]                  pp. 375-388
This study presents a review of how natural hazards can impact on immovable cultural heritage (ICH). In the last few decades, the global impact of natural hazards on cultural heritage appears to be growing, which in part, may be a response to the changes in the intensity and frequency of geomorphological processes in the light of climate and environmental change. Research undertaken at present by geographers, geologists, archaeologists, conservationists, and other specialists, shows significant interest in the protection, assessment, and mitigation of natural risk phenomena on ICH. However, attempts of evaluating the present state, and to predict the future degradation of cultural heritage is a real challenge. A review of the published literature indicates that the emergence of studies focused on the degradation of ICH by natural hazards started approximately 40 years ago, with an increasing trend starting from early in the 21st century; Europe is the most studied area globally. These studies demonstrate that conservation measures need to be implemented to protect and prevent further degradation of the world’s cultural heritage, to preserve a legacy for future generations.

Keywords: Immovable cultural heritage, Natural hazards, Mitigation, Conservation.

M.R. Singh, S.V. Kumar

Multi – Analytical Characterization of XVII Century Mughal Glaze Tiles from Northern India

[ Abstract ]
[ Full Article - PDF]                  pp. 389-400
Glazed tile art work is a technique that has been employed for decoration in most of the Mughal monuments during 16 – 17th Century in India. Dakhni Sarai is one of the finest and best preserved specimens of Mughal caravan sarais from India. Glaze tile samples of Dakhni Sarai were analyzed for glaze segments and colours that were used during the Mughal era. The samples were studied using stereomicroscopic analysis, EMPA – WDS, SEM - EDX and by thermal analysis using DTA/TGA. The EMPA-WDS results indicated the usage of lead colorants – tin for yellow glazes, copper - cobalt for blue glazes, and a mixture of two for green glaze tiles. The thickness and slip fusion of the tiles with the inner have also been studied. The result showed that oxides of copper/cobalt/lead used as colorant in varied proportion have imparted color to the glaze under different firing environment and temperature. The presence of copper/cobalt could be either due to its deliberate addition as part of the manufacturing process or as traces in raw material. The results proved that the manufacturing techniques of 16th century Mughal galze tile art work show resemblance to contemporary Persian tile works.

Keywords: Glazed tile; Colorant; Vitrification; Quartzite; Sillimanite; Firing environment; EPMA.

M. Afif, Mahirta

The Effectiveness of Sansevieria Trifasciata Cuticle Isolation to Protect Cultural Heritage Objects against Weathering caused by Rainwater

[ Abstract ]
[ Full Article - PDF]                  pp. 401-410
This research discusses the use of Sansevieria trifasciata as a natural water repellent for andesite and brick materials. Most of the outdoor cultural heritage objects are made of andesite and brick materials and are subject to disaggregation caused by rainwater. The decision to choose to isolate the cuticle of Sansevieria trifasciata based on knowledge that cuticle on plant can become water repellent on the plant and its availability is abundant in Indonesia. The authors isolated the cuticle of Sansevieria trifasciata for coating surface of andesite and brick materials and created an alternative solution by using natural substance against weathering of cultural heritage objects. The result shows that the cuticle isolation can effectively prevent the absorption of water on andesite but it cannot prevent absorption of the brick material. Although it’s effective to reduce water absorption for andesite, cuticle isolation has changed the surface colour of andesite and brick materials. Referring to the principles of cultural heritage management, cuticle isolation has changed the authenticity of the material. Therefore, in the future, more research is needed to achieve the transparent color of cuticle isolation before being applied to cultural heritage objects.

Keywords: Andesite; Brick; Coated; Cuticle; Rainwater; Sansevieria trifasciata, Weathering

A.A. Widati, A. Abdulloh, M. Khasanah, R. Kusumawati, N. Cahyandaru

Fabrication of Silica-Titania as Consolidant and Self Cleaning for the Conservation of Andesite Stone

[ Abstract ]
[ Full Article - PDF]                  pp. 411-418
The composites of silica-titania that have consolidant and self-cleaning property have been synthesized by mixing titania and colloidal silica. The coating of stone using silica-titania could improve the mechanical properties of andesite stone. In addition, the coating created the superhydrophilic properties and similar visual appearance with untreated andesite. The self-cleaning performance of treated andesite could remove the 92% of congo red and 67% of methylene blue as staining agents through photocatalysis process.

Keywords: Colloidal silica; Titania; Consolidant; Self-cleaning; Andesite

C.R. Vintu, I.N. Alecu, A. Chiran, E. Leonte, A.F. Jitareanu, M. Stefan

Researches on the Agrotouristic Offer of Guest Houses in Dornelor Bassin (Case Study)

[ Abstract ]
[ Full Article - PDF]                  pp. 419-430

Sustainability in the rural area of the Romanian economy is closely linked to the possibility of meeting the consumption needs of the population through a growing, permanent, diversified and high-quality offer, in line with current and potential consumer needs. The agrotourism offer targets a certain segment of the population (tourists), being represented by both material elements (food, non-food goods), but above all, by agrotouristic services, which comprise a wide range of activities. Agrotourism is a form of rural tourism, being closely related to the agrotouristic household, which is based on the existing resources in rural areas (agricultural, touristic, human, economic). Agrotourism includes both basic tourist activities (accommodation, tourist hiking, basic tourist services such as catering and accommodation) and additional services, plus a series of agricultural activities (plant cultivation, livestock breeding), as well as the processing of agricultural raw materials within the households (agrotourist guest houses) and the capitalization of finished products, both to the tourists accommodated in the guest house and to the markets and fairs in the area. The research was carried out in Dorna Basin and covered 35 touristic and agrotouristic guest houses, of which 11 which own agricultural land (arable, natural pastures, natural meadows) and animals (cattle, pigs, poultry) were selected. The research had an applicative character and was based on a questionnaire, which was administered to a panel of 11 boarders of agro-touristic guest houses located in the Dornelor Basin. The work has an original character, being the result of own research by the authors.

Keywords: Agrotourism; Tourism offer; Sustainability; Service quality; Dorna Basin; Romania

M.E. Osman, A.A. El-Shaphy, M.M. Ayid

Evaluation of the Inhibitory Effect of Dimethyl Sulfoxide on Fungal Degradated Archaeological Wood

[ Abstract ]
[ Full Article - PDF]                  pp. 431-440
Fungi play a very important role in deterioration of ancient wood antiques and therefore must not be neglected due to the increasing aesthetic value of art objects as well as the impact on health of conservators. A number of chemicals have been used for the treatment of museum artefacts. Biocides are the most effective at eradicating spores and mature organisms. Dimethyl sulfoxide (DMSO) is frequently used as a solvent for anti-fungal drugs. This study was carried out to evaluate in vitro and in vivo antifungal efficacy of DMSO against Aspergillus parasiticus. In vitro, fifty percent of DMSO gave complete inhibition of the growth. Also, 25% of DMSO inhibition growth by 60%. On the other hand low concentrations of DMSO were less effective. In vivo studies, treatment with DMSO on biodeteriorated sycamore wood resulted in inhibition of fungal growth. Furthermore, the application of DMSO had no effect on the colour, structure and chemical characteristic of the wood as well as, DMSO removed extraneous wood components that easily dissolve in DMSO.

Keywords: Biodeterioration; Wood treatment; Biocides; DMSO; Aspergillus parasiticus.

A.M. Rushdy, W.N. Wahba, M.S. Abd-Aziz, M. El Samahy, S. Kamel

A Comparative Study of Consolidation Materials for Paper Conservation

[ Abstract ]
[ Full Article - PDF]                  pp. 431-452
Historical paper is an essential part in cultural and economic progress of humanity.So, this study is to improve the physical-mechanical properties and stability of the brightness of historical paper by evaluating some consolidation materials, carboxymethyl cellulose, chitosan, BEVA 371, and soya bean flour, and to show the changes in paper properties, resulting from thermal accelerated ageing. Analytical techniques used for the evaluation process were pH measurements, tensile strength, burst strength,color change, and scanning electron microscopy (SEM). Also AgNP is deposited by the in situ reduction of silver nitrate on the treated paper sheets in the presence of citrate molecules as stabilizing agent. Antimicrobial activities of the paper sheets were also investigated against Gram positive bacterium Staphylococcus aureus, Gram negative bacterium Pseudomonas aeruginosa, yeast Candida albicans, and fungal Aspergillus niger which are model microorganisms for testing bactericidal properties. The result pointed out that chitosan and carboxymethyl cellulose lead to a significant improvement of the paper mechanical properties and AgNP containing papers gave an improvement as antimicrobial for all the consolidation materials.

Keywords: Paper conservation; Consolidation; Chitosan; Carboxymethyl cellulose; BEVA 371; Soya beans flour; Thermal ageing; Silver Nano-particles; Antimicrobial.

S. Sanchez-Sabau, M. Sabau, L. Montero, J. Gonzalez-Coneo, A. Abellan, C. Osorio

A Look to the Sustainable Draining Systems: Criteria of Sustainability and Successful Cases

[ Abstract ]
[ Full Article - PDF]                  pp. 453-464
There have been many studies and research that address sustainable drainage urban systems (SUDS), where factors like costs or the zone where a SUDS is to be installed are determinant, so multicriteria studies are important in decision-making. The development of a multidisciplinary approach could in the future serve as a helping tool to support decision, whose purpose would be to guide users in their choice of the most appropriate solution for managing the collection of rainwater. Another key point is to make use of other strategies to accurately define the most appropriate SUDS for a particular location. Modelling for example, considers different factors to simulate real-time rainfall events and evaluate the performance of rainwater collection systems among other low impact development systems. Based on what has been stated above, some successful cases currently performed all over the world were studied, where it is evident that green roofs can retain between 70% and 100% when rainfall is not high and peak reduction on these may reach 83.3%. Concrete and porous asphalt mixtures differ in their behaviour, but even so, they can maintain over time an average permeability between 0.41 cm/s and 0.22 cm/s, and similar values in the reduction of the infiltration capacity of 79.43% and 82.04% respectively.

Keywords: SUDS; Urban drainage; Low impact development; Rainwater; Green roofs; Permeable pavements.

N.B. Che, M.F. Nkemny, E.T. Atem, R. Giliba

The Correlation between Bushmeat Harvesting and Wildlife Abundance in the Tofala-Mone Forest Corridor, Cameroon

[ Abstract ]
[ Full Article - PDF]                  pp. 465-474
The use of sophisticated tools and unconventional methods in wildlife exploitation is a threat to wildlife conservation. This study analysed the influence of bushmeat harvesting on wildlife abundance in the Tofala-Mone Forest Corridor (TMFC), Cameroon. Data were collected across 8 villages using semi-structured questionnaires, in-depth interviews and transect survey. Descriptive and inferential statistical analyses were used for quantitative data while content analyses were used for qualitative data. The key finding revealed that the main reason for bushmeat harvesting was for income generation. Agriculture, large family sizes and motivation were some of the factors influencing harvesting. An average of 16.0 ± 2.0 animals was harvested weekly per harvester, giving an annual average of 272.8901tons per harvester. Annual bushmeat harvested stood at 2,665,156 Francs CFA (5,330 US Dollar) per harvester. Most harvesters (97.3 %) reported a decrease in wildlife abundance. Hunting time per catch was reported to be about 3.48 hours compared to lesser time in the past. A negative correlation was obtained between harvested wildlife species and scarce wildlife species. This suggested that bushmeat exploitation was a major threat to wildlife abundance in the study areas.

Keywords: Bushmeat harvesting; Wildlife abundance; Biodiversity conservation; Wildlife management; Household income; Cameroon.

H.S. Veena, R.S. Ajin, A.M. Loghin, R. Sipai, P. Adarsh, A. Viswam, P.G. Vinod, M.K. Jacob, M. Jayaprakash

Wildfire Risk Zonation in a Tropical Forest Division in Kerala, India: A Study using Geospatial Techniques

[ Abstract ]
[ Full Article - PDF]                  pp. 475-484
The forests of the Western Ghats in India are often affected by wildfires. Such forest fires are potential hazards seriously damaging the environment. Wildfire occurrence in an area is influenced by environment, terrain, and climatic conditions, alongside with human activities. The records on previous forest fire data show that the present study area is also prone to fires. The present study aims to delineate and map wildfire risk zones in Thenmala forest division, a part of the Western Ghats, using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Factors such as land use/land cover (LU/LC) type, slope, aspect, distance from settlement, distance from road, and elevation are selected for this study. All these factors have direct or indirect influence on fire occurrence. A Modified Fire Risk Index method has been used to prepare the fire risk zone map. The prepared fire risk zone map of Thenmala forest division has classified the area into five zones viz., very low, low, moderate, high, and very high. Finally, the risk zone map is validated with the fire incidence points, which shows that 75% of the fires have occurred in the high and very high risk zones. This shows the effectiveness of the present methodology and can be used for entire Western Ghats region. The study shows that the majority of fires are induced by humans. The officials of the forest departments can use this risk zone map to easily locate areas under high and very high fire risks and take effective preventive and mitigation measures. This can reduce loss of life and precious forest wealth.

Keywords: Wildfire; Modified Fire Risk Index; Incidence points; Western Ghats

S.K. Maharjan, K.L. Maharjan

State of Climate Policies, Plans/Strategies and Factors Affecting its Implementation in Nepal

[ Abstract ]
[ Full Article - PDF]                  pp. 485-496
Climate change is a complex and cross-cutting issue in Nepal that needs joint initiatives and efforts from all sectors at all levels to minimize its impacts. The government has developed climate policies, plans and frameworks – NAPA, National Climate Change Policy, LAPA and now in the process of developing National Adaptation Plans (NAPs). This paper has explored the views and experiences of climate experts in Nepal on state of climate policies, its inter-linkages, roles and responsibilities of ministries and departments, important factors to be considered and subjective indicators for effective implementation of policies. Altogether 30 experts responded the questionnaire sent via the email, LinkedIn and Skype Interview. The experiences of the experts’ ranges from 2 to 30 years in the field representing government and non-government sectors including media and independent experts. The policies in Nepal are progressing in more strategic direction with national and local priorities. LAPA is the framework to address the local climatic issues originated in Nepal. However, lack of clarity on roles and responsibilities and coordination among the ministries, departments and clear mechanisms for implementation of these policies, lack of sensitization and decentralization and delegation of finance and technologies and capacity of the stakeholders are the major challenges.

Keywords: Climate policy; Nepal; NAPA; LAPA; Climate experts

M.N. Tamalene, M.H..I. Almudhar

Local Knowledge of Management System of Forest Ecosystem by Togutil Ethnic Group on Halmahera Island, Indonesia: Traditional Utilization and Conservation

[ Abstract ]
[ Full Article - PDF]                  pp. 497-508
Logging and industrial mining have brought rapid change to the functions of forests. This also occurred on Halmahera Island, Indonesia. The Togutil ethnic group who lived in the Halmahera forest, especially in Buli village, had lost their local practical knowledge related to traditional forest conservation. This was due to the existence of nickel mining in their indigenous forest area. The study location was an area far from mining activity; therefore, local knowledge-based forest conservation practice could still be found. Research results show that the Togutil ethnic group on Halmahera Island, especially in the Akelamo and Oba, Tidore Kepulauan areas, had local knowledge of traditional forest ecosystem management through the classification of forest areas where there existed zones of food and medicinal plants, hunting, plantation and settlements, bird habitats, taboo, and watersheds. The classification of forest areas through a zone system was a conservative practice of biodiversity by maintaining local tradition.

Keywords: Local knowledge; Forest ecosystem management; Biodiversity; Togutil

O.S. Dairo, O.J. Soyelu

Consequences of Prolonged Agronomic Practices: Faunal Composition and Abundance in Cultivated and Fallowed Soils

[ Abstract ]
[ Full Article - PDF]                  pp. 509-518
Composition and abundance of soil fauna were compared between continuously cultivated and fallowed soils with a view to determining the impact of prolonged agronomic activities on biodiversity. The cultivated soils had been under continuous use for over a decade for arable crop production whereas the fallowed soils had been undisturbed for about twenty years. Soil samples were collected from selected plots using a soil auger and standard methods were applied in the laboratory to extract different types of soil fauna. Pitfall traps were also set up in the plots to collect surface-dwelling arthropods. Members of three phyla were identified in the study, namely, Annelida, Arthropoda (Class Arachnida, Chilopoda, Diplopoda, Entognatha, Insecta, Malacostraca, Pauropoda) and Nematoda (Class Adenophorea, Enoplea, Secernentea, Tylenchoidea). Nematodes were the most abundant fauna (50.7%) in sampled soils followed by Collembola (Entognatha) (15.2%) and Acari (Arachnida) (12.3%) while Pseudoscorpionida (Arachnida) (0.1%) was the least abundant. Generally, fallowed soils were significantly richer in soil fauna compared to cultivated ones. It was concluded that agronomic practices, especially on a continuously-cropped soil, would have a negative impact on faunal biodiversity. Environment-friendly farming systems that entail minimum tillage of the soil, adoption of non-chemical pest control strategies and regular soil tests were suggested as viable ways of conserving faunal biodiversity.

Keywords: Biodiversity; Minimum tillage; Non-chemical pesticides; Soil fauna; Species abundance.

N. Mohammed, K.S. Goudar, G. Getachew, H. Ibrahim

Human - Wildlife Conflict: Intensity of Domestic Damage Caused by Wild Animals Around Yegof National Forest Priority Area, South Wollo, Amhara Region, Ethiopia

[ Abstract ]
[ Full Article - PDF]                  pp. 519-528
Damage manifestations in terms of crop damage and livestock depredation are common in Ethiopia and reporting of such domestic damage in the vicinity of Yegof National Forest Priority Area was achieved by collecting information using the pretested semi-structured questionnaire from November 2013 to May 2014. The anubis baboon (Papio anubis) and grivet monkey (Chlorocebus aethiops) were identified as major crop pests and maize crop was more vulnerable than other crops. Increase in population of crop raiders was perceived reason for crop damage. Guarding was the best believed mitigation strategy. Though the informants lack remedial measures, some alternative was suggested to minimize primates through displacing them to other areas and remove them completely. Leopard (Panthera pardus) and striped hyaena (Hyaena hyaena) were reported as major predators of livestock and both accounts for a loss of 1,993 domestic animals, hitherto. Despite this loss, most of the informants had positive attitude. In conclusion, the study area demands for sustainable and culturally acceptable conservation solutions to mitigate domestic damage.

Keywords: Attitude; Crop damage; Human-wildlife conflict; Livestock predation; Local community; Yegof national forest priority area.

B. Subbaiyan, M. Visveshwari, V. Thangapandian

An Efficient Indirect Regeneration and Multiple Shoots Formation from Nodal Explant of Ceropegia Juncea Roxb.

[ Abstract ]
[ Full Article - PDF]                  pp.529-536
An effective protocol has been developed for indirect shoots regeneration from nodal explant of C. juncea. Explants were cultured on MS medium inclusion with alone 2,4-dichlorophenoxyacetic acid (2, 4-D), Thidiazuron (TDZ) or in combined with concentrations of 6-benzylaminopurine (BA) and Kinetin (KN) for callus induction. The best response (73.5%) was observed from nodal explants on MS medium 0.5mg/L 2,4-D in combination with 0.05mg/L BA.Thecalli derived from nodal explants were subcultured on MS medium supplemented with BA in combination with NAA or IAA for shoot induction. The more number of shoots (5.37) and shoot length (6.13cm) was observed on MS medium supplemented with 1.0 mg/L BA with 0.10mg/L NAA of shoot regeneration in nodal derived callus. Nodal callus derived microshoots gave the highest rooting percentage (77.9%), root numbers (9.75) and length of roots (5.32 cm) were observed on half strength MS basal medium Inclusion of 0.5 mg/L IBA. Regenerated plantlets with well-developed shoots and roots successfully transferred to soil. This protocol could be useful for conservation and cultivation of C. juncea.

Keywords: Ceropegia; Node; Callus initiation; 2,4-dichlorophenoxyacetic acid.

N.H. Nik Raikhan, A.R. Khairul Izwan

Novel Treatment of Heavily Oiled Wastewater using Pseudomonas Aeruginosa Nr.22 Producing Usable Free Fatty Acids (FFA)

[ Abstract ]
[ Full Article - PDF]                  pp. 537-544
Heavily oiled wastewater treatment has been great challenge to engineers to accomplish. Since there are too many water bodies are polluted with oil, chemical treatment could still give lots of negative side effects. We are recommending discharging the oil using our novel microbial approach. The strain Pseudomonas aeruginosa NR.22 (Ps.NR.22); an extracellular lipase producer isolated from a polluted lake in Malaysia has been proved to remove different oils from heavily oiled-wastewater with 59.0g/L oil concentration to about 70% lower in lesser than 48 hours with the addition of local source, mix grade 9.1g/L nitrogen compose. We measured the excess of oil using the standard Gravimetric method. Study of the factors affecting the percentage of oil removal have resulted 45°C as the best temperature, 200rpm shaking rate and 11% (v/v) 24 hours inoculum with 5.0x105cells/mL. Lipase activity were significantly high and go all along with the values of oil removed. Oil removal was recorded excellently high using combination of the best parameters; valued of 92.8±0.01% removed oil with lipase activity about 29.8±0.08U/mL and a very positive sign of growth through biomass of 6.0±0.1g/mL. FTIR was used to study the oil characterization in the wastewater before and after the treatment and the finding supported the lipase-oil removal Gravimetric report where oil was cut to simpler C-C bonds to 6 different types of free fatty acids (FFA), confirmed using GC-MS as lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), linoleic acid (C18:2), oleic acid (C18:1) and caprylic acid (C8:0). All of the listed FFA has great potential for biodiesel production.

Keywords: Pseudomonas aeruginosa NR.22; Oil; Wastewater; Lipase; Free fatty acid (FFA)

Publication date: 15.09.2017

Help | Terms of use | Contact
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.