Books by Simak, reviewed by Eric Weeks - Reviews of a half dozen of some more obscure fantasy and science fiction novels from the 70's. - http://www.physics.emory.edu/~weeks/if/talisman.html
Clifford Donald Simak Papers - Finding aid for a special collection at the University of Minnesota. - http://special.lib.umn.edu/findaid/xml/mss044.xml
Clifford Simak Fan Site - Selected bibliography with annotations, scans of cover art, information about discussion forum. - http://www.tc.umn.edu/~brams006/simak/
Clifford D. Simak - Biography, common themes, bibliography. - http://en.wikipedia.org/wiki/Clifford_D._Simak