APA استشهاد

Sagan Carl. (2000). Carl Sagan's cosmic connection: An extraterrestrial perspective. CUP.

استشهاد بنمط شيكاغو

Sagan Carl. Carl Sagan's Cosmic Connection: An Extraterrestrial Perspective. Cambridge: CUP, 2000.

MLA استشهاد

Sagan Carl. Carl Sagan's Cosmic Connection: An Extraterrestrial Perspective. CUP, 2000.