König, K., Weick, F., & Wink, M. (2008). Owls of the world (2nd ed.). Christopher Helm.
Lua i Stíl Chicago (17ú heag.)König, Klaus, Friedhelm Weick, agus Michael Wink. Owls of the World. 2nd ed. London: Christopher Helm, 2008.
Lua MLA (9ú heag.)König, Klaus, et al. Owls of the World. 2nd ed. Christopher Helm, 2008.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.