APA:
Petkov, Nikolai (2006). The ferruginous duck Aythya nyroca as a potential indicator species for tracking ecological changes at the Srebarna lake managed reserve (NE Bulgaria).
Acrocephalus, volume 27, issue 128/129, str. 37-43.
URN:NBN:SI:DOC-YQX1RLPD from http://www.dlib.si
MLA:
Petkov, Nikolai. "The ferruginous duck Aythya nyroca as a potential indicator species for tracking ecological changes at the Srebarna lake managed reserve (NE Bulgaria)."
Acrocephalus volume 27. issue 128/129 (2006) str. 37-43.
<http://www.dlib.si/?URN=URN:NBN:SI:DOC-YQX1RLPD>