APA

Clepper H. E., . (1971). Leaders of American conservation. New York: Ronald Press Co.

Chicago

Clepper Henry Edward, . 1971. Leaders of American conservation. New York: Ronald Press Co.

Harvard

Clepper H. E., . (1971). Leaders of American conservation. New York: Ronald Press Co.

MLA

Clepper Henry Edward, . Leaders of American conservation. New York: Ronald Press Co. 1971.