"Boundary Changes". Geographic Change Notes: Illinois. Population Division, United States Census Bureau. May 19, 2006. Archived from the original on August 6, 2010. Retrieved May 28, 2008.
"Boundary Changes". Geographic Change Notes: Illinois. Population Division, United States Census Bureau. May 19, 2006. Archived from the original on August 6, 2010. Retrieved May 28, 2008.