Hoberg, Adams & Rausch 1991. Revision of the genus Anophryocephalus Baylis, 1922 from pinnipeds in the Holarctic, with descriptions of Anophryocephalus nunivakensis sp. nov. and A. eumetopii sp. nov. (Tetrabothriidae) and evaluation of records from the Phocidae. Canadian Journal of Zoology, 69(6) 1991: 1653-1668