Cita APA (7a ed.)

Hull, C. L. (1930). Knowledge and purpose as habit mechanisms. [s.n.].

Cita Chicago Style (17a ed.)

Hull, Clark Leonard. Knowledge and Purpose as Habit Mechanisms. [S.l.]: [s.n.], 1930.

Cita MLA (9a ed.)

Hull, Clark Leonard. Knowledge and Purpose as Habit Mechanisms. [s.n.], 1930.