APA
Cropley A. J., . (1977). Lifelong education. New York: Pergamon Press.
Chicago
Cropley A J, . 1977. Lifelong education. New York: Pergamon Press.
Harvard
Cropley A. J., . (1977). Lifelong education. New York: Pergamon Press.
MLA
Cropley A J, . Lifelong education. New York: Pergamon Press. 1977.