Cita APA (7a ed.)

Nelson, K. (1974). Variations in children's concepts by age and category. [s.n.].

Cita Chicago Style (17a ed.)

Nelson, Katherine. Variations in Children's Concepts by Age and Category. [S.l.]: [s.n.], 1974.

Cita MLA (9a ed.)

Nelson, Katherine. Variations in Children's Concepts by Age and Category. [s.n.], 1974.