Cita APA (7a ed.)

Williamson, O. E. (1993). Opportunism and its critics. [s.n.].

Cita Chicago Style (17a ed.)

Williamson, Oliver E. Opportunism and Its Critics. [S.l.]: [s.n.], 1993.

Cita MLA (9a ed.)

Williamson, Oliver E. Opportunism and Its Critics. [s.n.], 1993.