APA

Hartmann F. H., . (1957). The relations of nations. New York: Macmillan Company.

Chicago

Hartmann Frederick H, . 1957. The relations of nations. New York: Macmillan Company.

Harvard

Hartmann F. H., . (1957). The relations of nations. New York: Macmillan Company.

MLA

Hartmann Frederick H, . The relations of nations. New York: Macmillan Company. 1957.