Ups and Downs" . The Emergence of Life on Earth . Rutgers University Press. ISBN   978-0-8135-2740-6 . http://books.google.com/?id=Fo7tQ5mG21IC&printsec=frontcover#PPA17,M1 . Retrieved 2009-01-21 .   ^ St. Augustine (ca. 391). "Part 19". De Genesi ad litteram imperfecti liber (The Literal Meaning of Genesis: An Unfinished Work) . Book 1 .   ^ Giraldus