Cita APA (7th ed.)

Bick, H. (1972). Ciliated protozoa: An illustrated guide to the species used as biological indicators in freshwater biology. World Health Organization.

Cita Chicago (17th ed.)

Bick, Hartmut. Ciliated Protozoa: An Illustrated Guide to the Species Used as Biological Indicators in Freshwater Biology. Geneva: World Health Organization, 1972.

Cita MLA (9th ed.)

Bick, Hartmut. Ciliated Protozoa: An Illustrated Guide to the Species Used as Biological Indicators in Freshwater Biology. World Health Organization, 1972.