Editors by W. H. Twenhopel. (1953). Principles of invertebrate paleontology: A revised and enlarged (2nd ed.). McGraw - hill.
Chicago-Zitierstil (17. Ausg.)Editors by W. H. Twenhopel. Principles of Invertebrate Paleontology: A Revised and Enlarged. 2nd ed. New York: McGraw - hill, 1953.
MLA-Zitierstil (9. Ausg.)Editors by W. H. Twenhopel. Principles of Invertebrate Paleontology: A Revised and Enlarged. 2nd ed. McGraw - hill, 1953.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.