^ (2014). National Audubon Society Guide to Marine Mammals of the World, Knopf. ISBN 9780375411410 (revised Jul 2018)
^Reeves, R., Stewart, B., Clapham, P. & Powell, J. (2012). 9780375411410, A.A. Knopf. ISBN 9780375411410 (revised Jan 2014)
^National Audubon Society, National Audubon Society StaffNational Audubon Society Guide to Marine Mammals of the World by NATIONAL AUDUBON SOCIETY and National Audubon Society Staff (2002, Hardcover)ISBN 9780375411410 (revised Aug 2017)