Spinoffs and Tie-ins
Dell Comics published a short-lived five issue comic book based on the series lasting from January 1968 to October 1969)
Two spin-off novels were written by Jack Pearl: the first a mass-market adult paperback published by Dell, called, simply GARRISON'S GORILLAS; the second aimed at the Young Adult (YA) market and published by Whitman, titled GARRISON'S GORILLAS AND THE FEAR FORMULA. Both are of course long out of print, but fairly easy to find at reasonable prices from eBay and other antiquarian & collectible book sites.
Though the first five seasons of "Combat!" are out on DVD, the sixth season, "Garrison's Gorillas", oddly is not.
Read more about this topic: Garrison's Gorillas