Merrick & Co. (2011). Height Modernization (ILHMP) LiDAR Data: Monroe County, Illinois: 2012. University of Illinois Urbana-Champaign, Illinois State Geological Survey. http://clearinghouse.isgs.illinois.edu/data/elevation/illinois-height-modernization-ilhmp-lidar-data

Available from: https://geo.btaa.org/catalog/8385b5b1-0e77-4275-8abe-f204d2ba9b6c