- Riedman 1990a
- The Pinnipeds: Seals, Sea Lions, and Walruses. University of California Press, Berkeley. 439 pp.
- Verboom, Kastelein 1995b
- The rutting whistles of a male Pacific walrus (Odobenus rosmaruas divergens), In: Sensory systems of Aquatic Mammals (eds. R. A. Kastelein, J. A. Thomas and P. E. Nachtigall), De Spil Publishers, Woerden Holland.
- Reeves 1992
- The Sierra Club Handbook of Seals and Sirenians. Sierra Club Books, San Francisco. 359 pp.
- Leatherwood, Reeves 1983
- The Sierra Club Handbook of Whales and Dolphins. Sierra Club Books, San Francisco. 302 pp.