Berta, A. & Churchill, M. (2012). “Pinniped Taxonomy: evidence for species and subspecies”. 《Mammal Review》 42 (3): 207–234. doi:10.1111/j.1365-2907.2011.00193.x. CS1 관리 - 여러 이름 (링크)
Berta, A.; Churchill, M. (2012). “Pinniped taxonomy: Review of currently recognized species and subspecies, and evidence used for their description”. 《Mammal Review》 42 (3): 207–34. doi:10.1111/j.1365-2907.2011.00193.x.