Cita APA (7a ed.)

Draper, R. J., Gerber, G. J., & Layng, E. M. (1990). Defining the role of pet animals in psychotherapy. [s.n.].

Cita Chicago Style (17a ed.)

Draper, Ronald J., Gary J. Gerber, y E. Marnie Layng. Defining the Role of Pet Animals in Psychotherapy. [S.l.]: [s.n.], 1990.

Cita MLA (9a ed.)

Draper, Ronald J., et al. Defining the Role of Pet Animals in Psychotherapy. [s.n.], 1990.