Cita APA (7a ed.)

Duffey, F. D. (1946). Fragua vocacional: (Testing the spirit). [s.n.].

Cita Chicago Style (17a ed.)

Duffey, Felix D. Fragua Vocacional: (Testing the Spirit). [S.l.]: [s.n.], 1946.

Cita MLA (9a ed.)

Duffey, Felix D. Fragua Vocacional: (Testing the Spirit). [s.n.], 1946.