Ghostbusters International Series by Erik Burnham, Dan Schoening, Rachael Stott

There's something strange in the neighborhood... and whether that neighborhood is in New York City or Venice, Italy, the Ghostbusters will be there! After a bust at the United Nations, the boys in gray are engaged to investigate an Old World haunting, where they begin to unravel a mystery that sends them around the globe (while still trying to keep their contract with the City, County, and State of New York!).

The team is still on the move as they head to Puerto Rico and Ireland as ghosts all over the world need to be busted while Egon chases a mystery about a powerful Scandinavian spell book. Collects issues #6-11.