Sentence:The purported author of the Nancy Drew mystery series, "Carolyn Keene", is actually a pseudonym for a series of [e1]ghostwriters[/e1] who write [e2]books[/e2] in the same style using a template of basic information about the book's characters and their fictional universe.
 e1: ghostwriters. 
 e2 : books.
Answer: Product-Producer(e2,e1)