APA استشهاد

Heck, A., & Perdang, J. (1991). Applying fractals in astronomy. Springer-Verlag.

استشهاد بنمط شيكاغو

Heck, A., و J.M Perdang. Applying Fractals in Astronomy. New York: Springer-Verlag, 1991.

MLA استشهاد

Heck, A., و J.M Perdang. Applying Fractals in Astronomy. Springer-Verlag, 1991.