He started it!

McCartney, Ono in Beatles Credits Dispute – Report
LOS ANGELES (Reuters) – Even though the Holidays are here Yoko Ono and Paul McCartney are not giving peace a chance.
Attorneys for the widow of former Beatle John Lennon are examining whether she has legal recourse after McCartney reversed the traditional “Lennon-McCartney” songwriting credit on his new album, the Los Angeles Times reported on Sunday.
The Times said 19 songs on McCartney’s live collection, “Back in the U.S.,” were credited to “Paul McCartney and John Lennon,” breaking a 40-year custom. Even Beatles songs written solely by McCartney, such as “Yesterday,” were always credited as “Lennon-McCartney.”
The paper said one of Ono’s lawyers indicated on Friday he was “looking into” whether or not she could take legal action to stop the modification of the credit.
The attorney told the Times the change in credit runs counter to an agreement the two made 40 years ago.
A spokesman for McCartney replied that the two never had a firm deal requiring the credits to be done in a certain way.