APA

Keller E. A., . (1992). Environmental geology. New York: Macmillan Publishing Company.

Chicago

Keller Edwrad A, . 1992. Environmental geology. New York: Macmillan Publishing Company.

Harvard

Keller E. A., . (1992). Environmental geology. New York: Macmillan Publishing Company.

MLA

Keller Edwrad A, . Environmental geology. New York: Macmillan Publishing Company. 1992.