APA Style

Weber, A., Burtt, B, L. (1997). Revision of the genus Ridleyandra (Gesneriaceae) . Berlin: Duncker and Hublot.

MLA Style

Weber, A.., Burtt, B., L.. "Revision of the genus Ridleyandra (Gesneriaceae)". Berlin: Duncker and Hublot, 1997. Text.