Simplify the following text for a Grade 9 native English-speaking person.
Original: After his death , Gilliand 's sister donated the `` Pop Chronicles '' tapes to the University of North Texas Music Library where they form The John Gilliland Collection .
Simplified: After his death , Gilliand 's sister donated the `` Pop Chronicles '' tapes to the University of North Texas Music Library . They form The John Gilliland Collection .