APA

Wesley Powell J., . (1969). Down the Colorado. New York: Promontory Press.

Chicago

Wesley Powell John, . 1969. Down the Colorado. New York: Promontory Press.

Harvard

Wesley Powell J., . (1969). Down the Colorado. New York: Promontory Press.

MLA

Wesley Powell John, . Down the Colorado. New York: Promontory Press. 1969.