Numerous sources were utilized in the preparation of these maps. Particular mention should be made of the Operational Navigational Charts (ONC) scale 1:1,000,000, Tactical Pilotage Charts (TPC) scale 1:500,000, Joint Operations Graphics (JOG) scale 1:250,000, Military Topographical Maps scale 1:126,000 prepared by the Imperial Russian Army in the 1860s and Military Topographical Maps scale 1:100,000 and 1:50,000 prepared by the Soviet Red Army in the 1930s. Topographical maps scale 1: 25,000 were used for making the maps of former German territory. Satellite imagery and aerial photography have also been used.
Many individuals have contributed valuable assistance during the research for these charts. Besides those whose names appear on individual maps, a special word of thanks should go to the staff of the Geography and Map Department at the Library of Congress in Washington, D.C. and to A. David Schroeder.
William Schroeder grew up on a farm near Horndean. He is a descendent of immigrants from the Bergthal Colony in Russia who settled in Manitoba in 1874. He received his high school education in Rosenheim, Horndean and Winkler, and obtained his Bachelor of Arts and Bachelor of Education degrees from the University of Manitoba.
A teacher by profession, Schroeder taught for eight years at Clover Plains near Morris and froml963 till 1989 in Winnipeg. He and his wife Augusta are the parents of four children, Trudy, Ken, David, and Richard. They are members of the Elmwood Mennonite Brethren Church in Winnipeg.
William Schroeder is also the author of the book The Bergthal Colony that was published in limited edition in 1973, by CMBC Publication in 1974 and as a revised edition in 1986.