Question: In 1991, The Ren & Stimpy Show was one of Nickelodeon's original three Nicktoons series along with Doug and which other show?
Sentence (from "Ren and Stimpy (characters)"): Ren and Stimpy, created by John Kricfalusi, are the title characters in the American-Canadian animated television series "The Ren & Stimpy Show".
Relevant evidence: Yes