Author Walter Everett in “The Beatles As Musicians: The Quarrymen Through 'Rubber Soul'” notes the Everlys were one of those, along with Carl and Jay Perkins and Buddy Holly who “first shaped the duets and trios of (John) Lennon, (Paul) McCartney and (George) Harrison.” Everett says the “oblique two-part descent” in the Beatles' “Please Please Me” was modeled on the Everlys' “Cathy's Clown.”
The Beatles themselves covered "So How Come (No One Loves Me)," which was sung by George Harrison, during the BBC sessions for their July 23, 1963 “Pop Goes the Beatles” show. According to authors Kevin Howlett and Mark Lewisohn, the Beatles were also known to have sung the Everlys' “I Wonder If I'll Care As Much” and “Cathy's Clown.” Howlett also adds “Love of My Life” to that list.
The Everlys' first record, “Bye Bye Love,” was issued in the UK the day before John Lennon and Paul McCartney met in July, 1957, according to Mark Lewisohn in “The Beatles: All These Years, Volume One: Tune In.” Harrison was a big fan of the record, Lewisohn notes. Paul McCartney later wrote "On the Wings of a Nightingale," which the Everly Brothers recorded for their album "EB '84."