Cita APA (7a ed.)

Orr, J. (1981). Hong Kong nudibranchs. Urban Council.

Cita Chicago Style (17a ed.)

Orr, John. Hong Kong Nudibranchs. Hong Kong: Urban Council, 1981.

Cita MLA (8a ed.)

Orr, John. Hong Kong Nudibranchs. Urban Council, 1981.