Longsworth, P. (1959). Exploring caves. Thomas Y. Crowell.
Cita Chicago Style (17a ed.)Longsworth, Polly. Exploring Caves. New York: Thomas Y. Crowell, 1959.
Cita MLA (9a ed.)Longsworth, Polly. Exploring Caves. Thomas Y. Crowell, 1959.
Precaución: Estas citas no son 100% exactas.