Hoffmeister, D.F. & de la Torre, L. (1961). "Geographic variation in the mouse Peromyscus difficilis". Journal of Mammalogy. 42 (1): 1–13. doi:10.2307/1377235. JSTOR1377235.
Hoffmeister, D.F. & de la Torre, L. (1961). "Geographic variation in the mouse Peromyscus difficilis". Journal of Mammalogy. 42 (1): 1–13. doi:10.2307/1377235. JSTOR1377235.