That's a good question. They seemed to like to cover alot of the black vocal groups and Carl Perkins, then 'Beatles' was an offshoot of the Crickets and most of you know how huge a Buddy Holly fan Macca is, he owns the rights to his catalog. I like alot of the early covers they did because songs like 'Chains' and 'Baby Its You' were just modest hits for others, they didn't necessarily go for covering the Number 1s of the day.