APA استشهاد

Bless, R. C. (2013). Discovering the cosmos (2nd ed.). University Science Books.

استشهاد بنمط شيكاغو

Bless, Robert C. Discovering the Cosmos. 2nd ed. Mill Valley, Calif.: University Science Books, 2013.

MLA استشهاد

Bless, Robert C. Discovering the Cosmos. 2nd ed. University Science Books, 2013.