Παραπομπή σε μορφή APA (7η εκδ.)

Webb, S. (2002). If the Universe is Teeming with Aliens... Where is Everybody?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life. Springer New York.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Webb, Stephen. If the Universe Is Teeming with Aliens... Where Is Everybody?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life. New York, NY: Springer New York, 2002.

Παραπομπή σε μορφή MLA (8th εκδ.)

Webb, Stephen. If the Universe Is Teeming with Aliens... Where Is Everybody?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life. Springer New York, 2002.