Gaya APA

Skinner, B, J., C.Porter, S. (1989). The Dynamic Earth an introduction to physical geology . the United States of America: JOHN WILEY & SONS, INC.

Gaya MLA

Skinner, Brian, J.., C.Porter, Stephen. "The Dynamic Earth an introduction to physical geology". the United States of America: JOHN WILEY & SONS, INC, 1989. Text.