Ichishima, H.; Kimura, M.. (2005). «Harborophocoena toyoshimai, a new early Pliocene porpoise (Cetacea, Phocoenidae) from Hokkaido, Japan» Journal of Vertebrate Paleontology 25 (3): 655–664. doi:10.1671/0272-4634(2005)025[0655:htanep]2.0.co;2..
Lambert, O.. (2008). «A new porpoise (Cetacea, Odontoceti, Phocoenidae) from the Pliocene of the North Sea» Journal of Vertebrate Paleontology 28 (3): 863–872. doi:10.1671/0272-4634(2008)28[863:ANPCOP]2.0.CO;2..