1978. Levinson, David M. and Chen, Wei. High-quality GIS land use maps for the Twin Cities Metropolitan Area for 1978 that were developed from paper maps (no GIS version existed previousl... University of Minnesota.
1968. Paul Jacobs, Rebecca Barney, Len Kne, Ya Tao, and Dan Milz. A digitized version of Ian McHarg's original 1968 Ecological Study for the Twin Cities Metropolitan Area: Composite Intrinsic Suitability. These ma... University of Minnesota Digital Conservancy.