Easa, P. S. A., & Jayson, E. A. A. (2004). A field guide to animal signs.
Chicago Style aipamenaEasa, P S; Author, and E A; Author Jayson. A Field Guide to Animal Signs. Thrissur, Kerala Forest Research Institute, 2004.
MLA aipamenaEasa, P S; Author, and E A; Author Jayson. A Field Guide to Animal Signs. 2004.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.