APA

Zern E. N., . (1928). Coal miners'pocketbook. New York: McGraw-Hill.

Chicago

Zern E N, . 1928. Coal miners'pocketbook. New York: McGraw-Hill.

Harvard

Zern E. N., . (1928). Coal miners'pocketbook. New York: McGraw-Hill.

MLA

Zern E N, . Coal miners'pocketbook. New York: McGraw-Hill. 1928.