Endo, H.; Sakata, S.; Arai, T.; Miyazaki, N. (April 2001). "The Muscles of Mastication in the Caspian Seal (Phoca caspica)". Anatomia, Histologia, Embryologia. 31 (5): 262–265. doi:10.1046/j.1439-0264.2002.00372.x. PMID12484416.
iucnredlist.org
Härkönen, T. (2008). "'Pusa caspica'". Diakses tanggal 29 January 2009.
nih.gov
ncbi.nlm.nih.gov
Endo, H.; Sakata, S.; Arai, T.; Miyazaki, N. (April 2001). "The Muscles of Mastication in the Caspian Seal (Phoca caspica)". Anatomia, Histologia, Embryologia. 31 (5): 262–265. doi:10.1046/j.1439-0264.2002.00372.x. PMID12484416.