From the author biographies in Ghostbusters: Who Ya Gonna Call?:
Matthew contributed the Ghostbusters Fact List. Basically, the GB Fact List lists every fact about the Ghostbusters, their tools, and their talents. The info was taken from the movies, cartoons, comic books, and a few fan conjectures that are now considered canon by GB fans, or "Ghostheads" as they're known as now. It has been formatted to go along with the Ghostbusters Omnibus Timeline. Ben King, A.K.A. Kingpin, and Matthew offer the Fact List as a guide to the backgrounds of the Ghostbusters and basically everything in their universe.