Music cassettes from student days have a system all of their own. As I was typically impoverished, I could not (generally) afford to buy more cassettes than necessary. As a result, although you will often find the artist on the 'A' side has no connection with that on the 'B'. The tapes are filed based on the 'A' side, so I'm the only person who stands a chance of finding a 'B' side without an exhaustive search.