The name of the library the group is trapped in is "Savini Library" which is a nod to Tom Savini who has worked with George Romero on his zombie movies.
A nod to Rocky Horror Picture Show - actually several, with "Brad and Janet" being the popular couple, and Eddie uttering the phrase "Dammit, Janet!"
As the end credits begin you hear a women say "attention all shoppers," its sounds like the exact same voice that announced a free bag of hard candy in the original Dawn of the Dead.
Ash is likely named after Bruce Campbell's character from the Evil Dead series.
There is a Return of The Living Dead ad on the back of the magazine Jimmy is reading in the library.