Here is a resource which is ideally suited to the Logos format, as it includes many, many references to other works (a lot of which are already Logos books). It is an ideal book for seminary/university students, which is when I first used it (actually the earlier Reinecker and Rogers Linguistic Key to the Greek New Testament). I still use it occasionally now in sermon preparation and academic study (part-time PhD at University of Aberdeen). I'm sure that as a study reference it has a place as a resource of first-resort. It would dovetail well with Zerwick.