Cita APA (7th ed.)

Harker, A. (1919). Petrology for students: An introduction to the study of rocks under the microscope (5th ed., rev.). The University Press.

Cita Chicago (17th ed.)

Harker, Alfred. Petrology for Students: An Introduction to the Study of Rocks Under the Microscope. 5th ed., rev. Cambridge [Eng.]: The University Press, 1919.

Cita MLA (8th ed.)

Harker, Alfred. Petrology for Students: An Introduction to the Study of Rocks Under the Microscope. 5th ed., rev. The University Press, 1919.