1. Adamczewska-Andrzejewska K., MackinRogalska R. & Nabaglo L. 1982. Rola systemów nor w powstawaniu fiuktuacji liczebnosci populacji nornika zwyczajnego, Microtus arvalis (Pall. 1779) [The role of burrows systems in inducing cyclic fiuctuations of the numbers of a common vole populations, Microtus arvalis (Pall. 1779)]. Wiad. Ekol. 28 (3/4): 181–198.
2. Baltag E., Pocora V., Sfîcă L. & Bolboacă L.E. 2013. Common Buzzard (Buteo buteo) population during winter season in NorthEastern Romania. the in fiuences of density, habitat selection, and weather. Ornis Fennica 90 (3): 186–192.
3. Bates D., Maechler M., Bolker B. & Walker S. 2014. Ime4: Linear mixedeffects models using Eigen and S4. R package version 1.1-7. http://CRAN.Rproject.org/package=lme4
4. Berry M.E., Bock C.E. & Haire S.L. 1998. Abundance of diurnal raptors on open space grasslands in an urbanized landscape. The Condor 100 (4): 601–608. DOI: 10.2307/1369742
5. Biby C.J., Burgess N.D., Hill D.A. & Mustoe S. 2000. Bird Census Techniques. Second Edition, 302 pp. ISBN: 978-0-12-095831-3