Cita APA (7a ed.)

Ehlers, E. G. (1982). Petrology: Igneous, Sedimentary, and Metamorphic. W. H. Freeman and Company.

Cita Chicago Style (17a ed.)

Ehlers, Ernest G. Petrology: Igneous, Sedimentary, and Metamorphic. San Francisco: W. H. Freeman and Company, 1982.

Cita MLA (9a ed.)

Ehlers, Ernest G. Petrology: Igneous, Sedimentary, and Metamorphic. W. H. Freeman and Company, 1982.