Cita APA (7a ed.)

Whittington, H. B. (1968). Cryptolithus (Trilobita): Specific characters and occurrence in Ordovician of Eastern North America.

Cita Chicago Style (17a ed.)

Whittington, Harry B. Cryptolithus (Trilobita): Specific Characters and Occurrence in Ordovician of Eastern North America. 1968.

Cita MLA (8a ed.)

Whittington, Harry B. Cryptolithus (Trilobita): Specific Characters and Occurrence in Ordovician of Eastern North America. 1968.