Cita APA (7th ed.)

Gregor, H. F. (1970). Geography of agriculture: Themes in research. Prentice-Hall.

Cita Chicago (17th ed.)

Gregor, Howard F. Geography of Agriculture: Themes in Research. Englewood Cliffs, N.J.: Prentice-Hall, 1970.

Cita MLA (8th ed.)

Gregor, Howard F. Geography of Agriculture: Themes in Research. Prentice-Hall, 1970.