Lisa the Vegetarian/References

References/Trivia

Trivia

This episode establishes Lisa's status as a vegetarian, an idea that was first hinted in the episode "Lisa's Wedding". One of Paul McCartney's stipulations for doing the guest spot was that Lisa's conversion to vegetarianism be a permanent one. Thus, it is an instance of continuity in the Simpsons universe that has been strictly held to.

The pig that Homer roasts and blasts into the air, flying over the nuclear power plant, is a direct reference to the cover of the Pink Floyd album Animals, which shows a pig flying over London's Battersea Power Station.
I Spit on Your Grave, a notorious exploitation film, is listed on the billboard for the drive-in cinema.

Numerous references to The Beatles are present in the episode. Apu claims to have met Paul during the Maharshi period. The Beatles' visit to this guru in India was a big media story in 1967. Apu then claims to have been called "The Fifth Beatle" (mispronouncing it to rhyme with "Seattle"), a claim which Paul does not seem to agree with. The way Apu pronounces Beatles is a reference to how the antagonists in the movie Help! say it.
Paul McCartney asks, "She's leaving home?", referencing the song of the same title from The Beatles' Sgt. Pepper's Lonely Hearts Club Band.
Lisa's remark, "Wow! Paul McCartney. I learned about you in history class", is a joke about the enormous cultural importance of the Beatles.
When Linda McCartney says "whenever we're in Springfield, we like to spend time in Apu's garden in the shade!" paraphrasing a lyric from the song "Octopus' Garden" (from the album Abbey Road).
The version of "Maybe I'm Amazed" that plays over the end credits is an original mix by the Simpsons staff that, when played backwards, contains snippets of Paul McCartney reciting a recipe for lentil soup – a throwback to an earlier gag. The recited recipe in forward speed can be found on the "Extras" section on Disc 1 of The Simpsons: Complete Season 7.
One of the backwards snippets says "Oh, and by the way, I'm alive." - a reference to the Paul is dead conspiracy theory.