Related Clues:

• Back of a record
• "P.S. I Love You," originally
• Elvis's 'Can't Help Falling In Love,' e.g
• Many an Everly Brothers hit
• Elvis' ''Hound Dog,'' for one
• Unlikely hit on a 45
• The Righteous Brothers' 'Unchained Melody,' originally
• Backtrack?
• 'I Am the Walrus,' for the Beatles' 'Hello, Goodbye'
• Queen's 'We Will Rock You,' to 'We Are the Champions'
• Back of a hit record
• One half of a 45
• Lesser-played part of a 45
• Musical flip
• Elvis's 'Viva Las Vegas,' recordwise