Mennonite Historical Atlas: Wilhelm Schroeder Maps
http://www.many-roads.com/ . Link to Prussian Yearbooks, maps, and Mennonites.
West Prussian Mennonites Villages: http://www.mennonitegenealogy.com/prussia/West_Prussian_Mennonite_Villages_Alph.htm
The many articles published by Adalbert Goertz.