Lennon or McCartney?: We May Finally Have The Answer

In interviews, John Lennon and Paul McCartney have explained that, though they were listed as co-writers for Beatles tunes, one or the other usually wrote most of a song.
McCartney wrote most or all of “Yesterday,” “Martha My Dear” and “Lady Madonna,” for example. Lennon wrote most or all of “Revolution,” “Help” and “Sexy Sadie.” Both had songwriting tendencies that enabled fans to usually figure out the primary writer. McCa