Cita APA (7th ed.)

Armstrong, D. M. (1989). Universals: An opinionated introduction. Westview.

Cita Chicago (17th ed.)

Armstrong, D. M. Universals: An Opinionated Introduction. Boulder: Westview, 1989.

Cita MLA (9th ed.)

Armstrong, D. M. Universals: An Opinionated Introduction. Westview, 1989.