Martin, a Mennonite family tree, the first five generations : the story of the descendants of Christian & Ellis Martin, Swiss-German settlers to Lanaster County, Pennsylvania, 1732
The Goodyear family : the descendants of Johann Christian Gutjahr & Margaretha Roesner (particularly their sons Frederick and Ludwig, with some references to sons John Christian, Jr., and George)
initial research done by Ralph Frederick and Clara H. Goodyear ; expanded by the cooperative work of numerous cousins ; as edited by Ralph W. Donnelly and Sarah E. Rivoir.