Young & Bannasch 2007, p. 49. Young, Amy; Bannasch, Danika (2007). "Chapter 4: Morphological variation in the dog". In Ostrander, Elaine A.; Giger, Urs; Lindblad-Toh, Kerstin (eds.). The Dog and its Genome. Cold Spring Harbor, New York: Cold Spring Harbor Laboratory Press. pp. 47–66. ISBN9780879697815.
Young & Bannasch 2007, p. 48-49. Young, Amy; Bannasch, Danika (2007). "Chapter 4: Morphological variation in the dog". In Ostrander, Elaine A.; Giger, Urs; Lindblad-Toh, Kerstin (eds.). The Dog and its Genome. Cold Spring Harbor, New York: Cold Spring Harbor Laboratory Press. pp. 47–66. ISBN9780879697815.