Literature
  • Ridgeway, 1981a
  • Handbook of Marine Mammals, Volume 1: The Walrus, Sea Lions, Fur Seals and Sea Otter. Academic Press, London. 235 pp.
  • Ridgeway, 1981b
  • Handbook of Marine Mammals, Volume 2: Seals. Academic Press, London. 359 pp.
  • Ridgeway, 1985
  • Handbook of Marine Mammals, Volume 3: The Sirenians and Baleen Whales. Academic Press, London. 362 pp.
  • Ridgeway, 1989
  • Handbook of Marine Mammals, Volume 4: River Dolphins and the Larger Toothed Whales. Academic Press, London. 442 pp.