Cita APA (7a ed.)

Egeland, J., Sandoz, Y., & Doswald-Beck, L. (1987). Preface. [s.n.].

Cita Chicago Style (17a ed.)

Egeland, Jan, Yves Sandoz, y Louise Doswald-Beck. Preface. [S.l.]: [s.n.], 1987.

Cita MLA (9a ed.)

Egeland, Jan, et al. Preface. [s.n.], 1987.