Parents' Magazine #12/1977

Includes an article by Ron Carnell titled "Clean Up the Comic Book Badlands, Now" in which he gives various Marvel and DC comics his own particular letter rating grade. Some, like Super-Villain Team-Up and Son of Satan get an "X" rating. As mentioned in The Comics Journal #40 (June 1978) in the article titled "Comic Book Badlands (Rated 'X')" (page 5).