Marzluff, J.: Clark's Nutcracker (Nucifraga columbiana). [w:] del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (red.). Handbook of the Birds of the World Alive [on-line]. Lynx Edicions, Barcelona, 2020. [zarchiwizowane z tego adresu (2020-05-11)].
Marzluff, J.: Clark's Nutcracker (Nucifraga columbiana). [w:] del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (red.). Handbook of the Birds of the World Alive [on-line]. Lynx Edicions, Barcelona, 2020. [zarchiwizowane z tego adresu (2020-05-11)].
William B. Davis & James Stevenson. The Type Localities of Three Birds Collected by Lewis and Clark in 1806. „The Condor”. 36 (4), s. 161–163, 1934. JSTOR: 1363415. (ang.).
