View all references for Sea squirts, fish, reptiles, birds and mammals (phylum Chordata)
(2008). Sea Mammals: Seals Page. www.glaucus.org.uk/seals1.htm, 2008-03-13 00:00:00
(1977). The handbook of British Mammals. 2nd edition. Blackwell Scientific Publications, Oxford & London.
(2001). Marine mammals: biology and conservation New York: Kluwer Academic / Plenum Publishers
(1974). British Seals. London : Collins
(1997). The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]
(2002). Photographic Guide to the Marine Mammals of the North Atlantic. Oxford: Oxford University Press.
(2003). Walker's Marine Mammals of the World. Baltimore: John Hopkins University Press.
(2008). Vagrant Seals in Shetland. www.nature-shetland.co.uk/seamammal/rareseals.htm, 2008-03-13 00:00:00