Simplify the following text for a Grade 5 native English-speaking person.
Original: Along with his own compositions , Zevon recorded or performed occasional covers , including Bob Dylan 's `` Knockin ' on Heaven 's Door '' and Leonard Cohen 's `` First We Take Manhattan '' .
Simplified: Zevon sometimes recorded or sang cover songs . He liked to sing Bob Dylan 's `` Knockin ' on Heaven 's Door '' and Leonard Cohen 's `` First We Take Manhattan '' .