Gould, S J. 1989. Wonderful Life: The Burgess Shale and the Nature of History. New York, N.Y.: W. W. Norton Co.
Gould, S J. 1999. Rocks of Ages: Science and Religion in the Fullness of Life. New York: Ballantine.
Lewontin, R C. 1978. Adaptation. Scientific American 239, no. 3: 213-30.
Ruse, M. 2003. Darwin and Design: Does Evolution have a Purpose? Cambridge, Mass.: Harvard University Press.
Whewell, W. [1853]2001. Of the Plurality of Worlds. A Facsimile of the First Edition of 1853: Plus Previously Unpublished Material Excised by the Author Just Before the Book Went to Press; and Whewell's Dialogue Rebutting His Critics, Reprinted from the Second Edition . Chicago: University of Chicago Press.