APA

Key V. O., . (1952). Politics, parties, and pressure groups. New York: Crowell.

Chicago

Key V O, . 1952. Politics, parties, and pressure groups. New York: Crowell.

Harvard

Key V. O., . (1952). Politics, parties, and pressure groups. New York: Crowell.

MLA

Key V O, . Politics, parties, and pressure groups. New York: Crowell. 1952.