Please excuse this post from having any sense of taste today. Signed, Epstein's Mother.
1947--IT HAPPENED IN BROOKLYN--The earliest appearance of James Buchanan High School. (Not named such, but the same building is used, and both are set in Brooklyn, even though the school used is really Gabe Kaplan's real childhood school, New Utrecht High School.)
1972--SUPER FLY--Apparently the car from this film later is purchased by teen Vinnie Barbarino.
1975--THE GREAT TV SITCOM BOOK--The Sweathogs are locked up by Barney Miller. Additionally, in the DVD extras for Welcome Back Kotter, Vinnie Barbarino is at the 12th Precinct (in John Travolta's screen test).
1975 to 1979--WELCOME BACK, KOTTER--Former gang member Gabe Kotter returns to his old high school as a teacher.
1976--FONZIE FAVORITES--The Fonzerelli Slide"--Fonzie shows up at the Annual Sweathogs School Dance and meets Horshack. You can find the evidence here.
1976 to 1978--WELCOME BACK, KOTTER (DC COMICS)--The show's popularity spawned a licensed comic book, which had one crossover linking it to the DC Universe (well, Earth-1 at least) in Superman versus Muhammad Ali, where the DC Comics version of the characters appeared on the cover.
Fall 1976--MR. T AND TINA--This was a spin-off of Welcome Back Kotter featuring Pat Morita as brilliant Japanese inventor Taro Takahashi, or Mr. T for short. Takashashi had previously appeared in an episode of Welcome Back, Kotter to set up the premise of the spin-off. Other spin-offs that failed to launch were RICH MAN, POOR MAN; HORSHACK!, which started with an episode of Welcome Back, Kotter that focused on the Horshack family, and a planned show that would have featured the grown up Sweathogs (minus Travolta).