How is a list of his appearances on other people s albums trivia It s basic discographical information And as you can see it s standard content for rappers discographies Also the sources in the album articles must be sufficient if the album listings themselves don t need to be sourced which seems to be the case per other high quality articles Bob Dylan Discography Elvis Presley Discography The Beatles Discography etc I could see a case for sourcing anything that doesn t have its own article however