Cita APA (7a ed.)

Kenworthy, L. S., & Birdie, R. A. (1969). Free and inexpensive materials on world affairs (3rd ed.). Teachers College Press.

Cita Chicago Style (17a ed.)

Kenworthy, Leonard Stout, y Richard A. Birdie. Free and Inexpensive Materials on World Affairs. 3rd ed. New York: Teachers College Press, 1969.

Cita MLA (9a ed.)

Kenworthy, Leonard Stout, y Richard A. Birdie. Free and Inexpensive Materials on World Affairs. 3rd ed. Teachers College Press, 1969.