Dyfyniad APA

Shrock, R. R., & Twenhofel, W. H. (1953). Principles of invertebrate paleontology.2nd ed (2nd ed.). McGraw hill.

Dyfyniad Arddull Chicago

Shrock, Robert R., and William H. Twenhofel. Principles of Invertebrate Paleontology.2nd Ed. 2nd ed. London: McGraw hill, 1953.

Dyfyniad MLA

Shrock, Robert R., and William H. Twenhofel. Principles of Invertebrate Paleontology.2nd Ed. 2nd ed. McGraw hill, 1953.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.