APA Edition Citation

Twenhofel, W. H., & Shrock, R. R. (1953). Principles of invertebrate paleontology (2d ed.). McGraw-Hill.

Chicago Edition Citation

Twenhofel, William H., and Robert R. Shrock. Principles of Invertebrate Paleontology. 2d ed. New York: McGraw-Hill, 1953.

MLA Edition Citation

Twenhofel, William H., and Robert R. Shrock. Principles of Invertebrate Paleontology. 2d ed. McGraw-Hill, 1953.