1. Conceptual gaps in the national strategy for the implementation of the European Natura 2000 conservation policy in Greece;Apostolopoulou;Biol. Conserv.,2009
2. Parks in Peril: People, Politics, and Protected Areas;Brandon,1998
3. Birds of Western Palearctic Interactive, 2006. Birdguides, Oxford University Press, UK (DVD-ROM).
4. BirdLife International, 2012a. Otis tarda. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. (downloaded 13.07.12).
5. BirdLife International, 2012b. Anser erythropus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. (downloaded 10.06.12).