Derek Goodwin: Crows of the world. 2. Auflage. Natural History Museum Publications, 1986, S.137 (archive.org).
doi.org
Antonio Rolando, Ian James Patterson: Range and movements of the Alpine ChoughPyrrhocorax graculus in relation to human developments in the Italian Alps in summer. In: Journal für Ornithologie. Band134, Nr.3, Juli 1993, ISSN0021-8375, S.338–344, doi:10.1007/BF01640430 (springer.com [abgerufen am 13. Juli 2022]).
springer.com
link.springer.com
Antonio Rolando, Ian James Patterson: Range and movements of the Alpine ChoughPyrrhocorax graculus in relation to human developments in the Italian Alps in summer. In: Journal für Ornithologie. Band134, Nr.3, Juli 1993, ISSN0021-8375, S.338–344, doi:10.1007/BF01640430 (springer.com [abgerufen am 13. Juli 2022]).
zdb-katalog.de
Antonio Rolando, Ian James Patterson: Range and movements of the Alpine ChoughPyrrhocorax graculus in relation to human developments in the Italian Alps in summer. In: Journal für Ornithologie. Band134, Nr.3, Juli 1993, ISSN0021-8375, S.338–344, doi:10.1007/BF01640430 (springer.com [abgerufen am 13. Juli 2022]).