Cita APA (7a ed.)

Ayer, A. M. (1926). Some difficulties in elementary school history. Columbia University.

Cita Chicago Style (17a ed.)

Ayer, Adelaide M. Some Difficulties in Elementary School History. New York: Columbia University, 1926.

Cita MLA (8a ed.)

Ayer, Adelaide M. Some Difficulties in Elementary School History. Columbia University, 1926.