^Mora, J. R. (2007). The Estrela Mountain Dog: A Flock-Guardian (illustrated ed.). J. R. Mora. ISBN9780955087011.
^Pugnetti, Gino (1980). Schuler, Elizabeth Meriwether (ed.). Simon & Schuster's Guide to Dogs. New York, London, Toronto, Sydney, Tokyo, Singapore: Simon & Schuster. p. 90. ISBN0-671-25527-4.