Swash, A & R Still 2005. Birds, Mammals and Reptiles of the Galapagos Islands, 2nd ed. Christopher Helm and Wildguides Ldt. ISBN 978-0-7136-7551-1
Swash, A & R Still 2005. Birds, Mammals and Reptiles of the Galapagos Islands, 2nd ed. Christopher Helm and Wildguides Ldt. ISBN 978-0-7136-7551-1