Cita APA (7th ed.)

Sparker, L. S., & Gallagher, J. S. (2007). Galaxies in the universe: An introduction (2a. ed.). Cambridge University Press.

Cita Chicago (17th ed.)

Sparker, Linda S., i John S. Gallagher. Galaxies in the Universe: An Introduction. 2a. ed. Nueva York: Cambridge University Press, 2007.

Cita MLA (9th ed.)

Sparker, Linda S., i John S. Gallagher. Galaxies in the Universe: An Introduction. 2a. ed. Cambridge University Press, 2007.