APA

Shimer H. W., Shrock R. R., . (1944). Index fossils of North America. New York: J.Wiley.

Chicago

Shimer Hervey W, Shrock Robert R, . 1944. Index fossils of North America. New York: J.Wiley.

Harvard

Shimer H. W., Shrock R. R., . (1944). Index fossils of North America. New York: J.Wiley.

MLA

Shimer Hervey W, Shrock Robert R, . Index fossils of North America. New York: J.Wiley. 1944.