It is not the person who wrote the song / performed the song that is important, it is the person / organisation who own the rights.

Rights to songs really are the oil of the music industry - owning the rights to some old beatles stuff is the only thing currently keeping M Jackson out of debtors jail (I think) - thay are gold dust and are jealously guarded - extreme caution advised for any commenrcial use. All this must keep thousands of laywers rich.