Παραπομπή APA

Freidel, F. (1960). America in the twentieth century. Alfred A koope.

Παραπομπή Chicago Style

Freidel, Frank. America in the Twentieth Century. New York: Alfred A koope, 1960.

Παραπομπή MLA

Freidel, Frank. America in the Twentieth Century. Alfred A koope, 1960.