Tolong jelaskan mengenai Sumber buku dari Carl Sagan

Sagan Medal for Excellence in Public Communication in Planetary Science, presented by the American Astronomical Society's Division for Planetary Sciences (AAS/DPS)

Carl Sagan Center for the Study of Life in the Universe, SETI Institute

Carl Sagan's Life and Legacy as Scientist, Teacher, and Skeptic, Committee for Skeptical Inquiry

Cosmos—Full Episodes and Clips streaming online for free—Hulu , Cosmos online for free

A Tribute to Carl Sagan: Our Place in the Universe, The Skeptics Society