Gaya APA

Shrock, R, R. (1953). Principles of Invertebrate Paleontology A Resived and Enlargen Edition of Twenhofel and Shrock, Invertebrate Pateonlogy . New York: McGraw-Hill Book Company, Inc.

Gaya MLA

Shrock, Robert,, R.. "Principles of Invertebrate Paleontology A Resived and Enlargen Edition of Twenhofel and Shrock, Invertebrate Pateonlogy". New York: McGraw-Hill Book Company, Inc, 1953. Text.