APA
(1968). Standard reference encyclopedia yearbook 1967. New York: Standard Reference Works Publishing Company, Inc.
Chicago
1968. Standard reference encyclopedia yearbook 1967. New York: Standard Reference Works Publishing Company, Inc.
Harvard
(1968). Standard reference encyclopedia yearbook 1967. New York: Standard Reference Works Publishing Company, Inc.
MLA
Standard reference encyclopedia yearbook 1967. New York: Standard Reference Works Publishing Company, Inc. 1968.
