References
- [1] Kranz A. Otters (Lutra lutra) increasing in Central Europe: from the threat of extinction to locally perceived overpopulation? Mammalia. 1998, 64, 4, 357-368.
- [2] Adamek Z, Kucerova M, Roche K. The role of common carp (Cyprinus carpio) in the diet of piscivorous predators – cormorants (Phalacrocorax carbo) and otter (Lutra lutra). Bull. VURH Vodnany. 1999, 4, 185–193.
- [3] Adamek Z, Kortan D, Lepic P, Andreji J. Impacts of otter (Lutra lutra L.) predation on fishponds: A study of fish remains at ponds in the Czech Republic. Aquaculture International. 2003, 11, 389–396.10.1023/A:1025787330366
- [4] Kortan D, Adamek Z, Polakova S. Winter predation by otter, Lutra lutra on carp pond systems in South Bohemia (Czech Republic). Folia Zool. 2007, 56, 4, 416–428.
- [5] English Nature. Retrieved 2010, 03-15.
- [6] Conroy J, Chanin P. The status of the Eurasian otter (Lutra lutra) in Europe – a review. Proceedings of the first otter toxicology conference, Eds., Conroy, J. W. H., Yoxon, P. and Gutleb, A. C.) 2000, 7-29.
- [7] Ruiz-Olmo J, Loy A, Cianfrani C, Yoxon P, Yoxon G, de Silva PK, Roos A., Bisther M, Hajkova P, Zemanova B, 2008. Lutra lutra. In: IUCN Red List of Threatened Species. 2008, Retrieved 21 March 2009.
- [8] Kruuk H, Moorhouse A, Conroy J W, Durbin L, Freares S. An estimate of numbers and habitat preferences of otters Lutra lutra in Shetland, U.K. Biological Conservation. 1989, 49, 241-254.
- [9] Reuther C. Development in weight and length of cubs of the Eurasian otter (Lutra lutra). IUCN Otter Specialist Group Bulletin. 1999, 16, 1, 11-25.
- [10] Kranz A.. On the ecology of otters in central Europe. Doctoral thesis. 1995, University of Agriculture, Vienna.
- [11] Green J, Green, R. and Jefferies, D. J. A radio-tracking survey of otters Lutra lutraon a Perthshire river system. Lutra. 1984, 27, 85-145.
- [12] Spiridonov G, Spassov N. The otter (Lutra lutra L., 1758) in Bulgaria, its statе and conservation. - Historia naturalis bulgarica. 1989, 1, 57-63.
- [13] Spiridonov G, Mileva L. The status of otter (Lutra lutra) in Bulgaria. Seminar on the Conservation of the European Otter (Lutra lutra), Leeuwarden, the Netherlands, 7-11 June 1994, Council of Europe, Strasbourg. 1994, 77-80.
- [14] Peshev Ts, Peshev D, Popov V. Fauna Bulgarica: Mammalia.Vol. 27. 2004, Marin Drinov Acad. Publ.
- [15] Georgiev D,. Diet of the Otter Lutra lutra in Different Habitats of South-Eastern Bulgaria. IUCN Otter Spec. Group Bull. 2006, 23, 1, 4 – 10.
- [16] Georgiev D. The fish species participation in otter’s (Lutra lutra) diet in Maritza river, West of Plovdiv town (Southern Bulgaria). Animalia. 2006, 42, 153–159.
- [17] Georgiev D, Stoicheva SFreshwater crabs preyed on by the Eurasian Otter Lutra lutra in a river habitat of southern Bulgaria. Hystrix It. J. Mamm. 2006, 17, 2, 129-135.
- [18]Georgiev D, Stoycheva S. Habitats, Distribution and Population Density Otter Survey in the Western Rhodopes Mountains (Southern Bulgaria) IUCN Otter Spec. Group Bull. 2006, 23, 1, 35 – 43.
- [19] Georgiev D. Study on the Home Range of the Resident Female Otter (Lutra lutra), (Carnivora, Mammalia) in South-East Bulgaria. Acta zool. bulg., 2007, 59, 2, 165-172.
- [20] Georgiev D. Otter (Lutra lutra L.) Mortalities in southern Bulgaria: a case study. IUCN Otter Spec. Group Bull. 2007, 24, 1.
- [21] Georgiev D. Size of Marsh frogs in the diet of Eurasian otter in southern Bulgaria. Hystrix It. J. Mamm. 2008, 19, 1, 55-59
- [22] Georgiev D. Ecological monitoring study of the otter (Lutra lutra L.) in the catchments of Tundzha and Maritsa Rivers. PhD Thesis, University of Plovdiv, Faculty of Biology, Department of Ecology and Environmental Conservation. 2008, 200 p.
- [23] Georgiev D. Eurasian Otters In Micro Dams Of Southern Bulgaria: Where To Place The Monitoring Zones? IUCN Otter Spec. Group Bull. 2009, 26 (1) 5 – 9.
- [24] Dimitrova R, Georgiev D. The Otter (Lutra lutra L.) Signs and the Banks Tree Cover: A Survey in Central and Eastern Bulgaria. Ecologica Balkanica, 2012, 4, 2, 1-4.
- [25] Georgiev D. Materials on the diet of the Otter (Lutra lutra L.) in the West Rhodopes Mountain, South Bulgaria. Ecologica Balkanica. 2013, 5, 1, 137-139.
- [26] Wood R, Gerald L. The Guinness Book of Animal Facts and Feats. 1983, Sterling Pub Co Inc.
- [27] Manson CF, Macdonalds SM. Otters: Ecology and Conservation. 1986, Cambridge University Press.
- [28] Chanin P. Monitoring the Otter. 2010, Conserving Natura 2000 Rivers, English Nature.
- [29] Pagett M. What Shat That?: A Pocket Guide to Poop Identity. 2007.
- [30] Brown RW, Lawrence MJ, Pope J. Animals. Tracks & Signs. 1984. Hamlyn. p. 225.
- [31] Erlinge S. Food habits of the otter (Lutra lutra L) and the mink (Mustela visonSchreber) in a trout water in southern Sweden. Oikos. 1969, 20, 1-7.10.2307/3543739
- [32] de Silva P. Food and feeding habits of the Eurasian Otter lutra lutra L. (Carnivora, Mustelidae) in Sri Lanka. Journal of South Asian Natural History. 1996, 2, 1, 81-90.
- [33] de Silva P. Seasonal variation of the food and feeding habits of the Eurasian otter Lutra lutra L. (Carnivora, Mustelidae) in Sri Lanka. Journal of South Asian Natural History. 1997, 2, 2, 205-216.
- [34] Kruuk H, Kanchanasaka B, O'Sullivian, S Wanghongsa S. Niche separation in three sympatric otters Lutra perspicillata, Lutra lutra and Aonyx cinerea in Huai Kha Khaeng, Thailand. Biological Conservation. 1944, 69: 115-210.
- [35] Stojanov A. Order anurans. In: Biserkov V. (Editor). A field guide to Amphibians and Reptiles of Bulgaria. Sofia. Green Balkans. 2007, 39-62.
- [36] Stojanov A, Tzankov N, Naumov B. Die Amphibien und Reptilien Bulgariens. 2011, Chimaira, Frankfurt am Main, Germany.