20.
Vassilev, K, Dajič, Z, Cušterevska, R, Bergmeier, E and Apostolova, I 2012. Balkan Dry Grasslands Database. – In: Dengler, J., Oldeland, J., Jansen, F., Chytrý, M., Ewald, J., Finckh, M., Glöckler, F., Lopez-Gonzalez, G., Peet, R.K., Schaminée, J.H.J. (Eds.) Vegetation databases for the 21st century.