APA

Erdos P. L., Morgan A. J., . (1970). Professional mail surveys. New York: McGraw-Hill.

Chicago

Erdos Paul L, Morgan Arthur James, . 1970. Professional mail surveys. New York: McGraw-Hill.

Harvard

Erdos P. L., Morgan A. J., . (1970). Professional mail surveys. New York: McGraw-Hill.

MLA

Erdos Paul L, Morgan Arthur James, . Professional mail surveys. New York: McGraw-Hill. 1970.