Não informado. (2001). Annual Report of the Board of Directors of the Zoological Society of Philadelphia. Zoological Society of Philadelphia.
Style de citation Chicago (17e éd.)Não informado. Annual Report of the Board of Directors of the Zoological Society of Philadelphia. Philadelphia, Pa: Zoological Society of Philadelphia, 2001.
Style de citation MLA (8e éd.)Não informado. Annual Report of the Board of Directors of the Zoological Society of Philadelphia. Zoological Society of Philadelphia, 2001.
Attention : ces citations peuvent ne pas être correctes à 100%.