November 4 1956
Howard T. Fisher & John D. Randall Associates, Inc.
January 24 1957
Howard T. Fisher & John D. Randall Associates, Inc.
April 23 1985
Forest Preserve District of DuPage County
March 11 1970
Steinbrecher Jr., Harold F.
April 1984
Forest Preserve District of DuPage County
October 10 – November 20 1940
Steinbrecher, Harold F.
May 25 2001
Earth Tech
August 1921
O. C. Simonds & Co.
April 10 1970
Steinbrecher Jr., Harold F.
October 10 – November 20 1940
Steinbrecher, Harold F.
circa 1970
Chicago Aerial Survey Co.
August 1921
O. C. Simonds & Co.
circa 1970
Chicago Aerial Survey Co.
February 24 2004
Christopher B. Burke, Engineering West, Ltd.
July 1921
O. C. Simonds & Co.
circa 1970
Chicago Aerial Survey Co.
February 24 2004
Christopher B. Burke, Engineering West, Ltd.
July 1921 – October 1922
O. C. Simonds & Co.