Yom-Tov, Yoram (June 1974). "The effect of food and predation on breeding density and success, clutch size and laying date of the crow (Corvus corone L.)". Journal of Animal Ecology. 43 (2): 479–498. Bibcode:1974JAnEc..43..479Y. doi:10.2307/3378. JSTOR3378.
Yom-Tov, Yoram (June 1974). "The effect of food and predation on breeding density and success, clutch size and laying date of the crow (Corvus corone L.)". Journal of Animal Ecology. 43 (2): 479–498. Bibcode:1974JAnEc..43..479Y. doi:10.2307/3378. JSTOR3378.
Yom-Tov, Yoram (June 1974). "The effect of food and predation on breeding density and success, clutch size and laying date of the crow (Corvus corone L.)". Journal of Animal Ecology. 43 (2): 479–498. Bibcode:1974JAnEc..43..479Y. doi:10.2307/3378. JSTOR3378.
kongehuset.no
"The Bird Room". The Norwegian Royal Family - Official Website. The Norwegian Royal Family. 3 February 2007. Retrieved 2008-03-17.