Id Url Resource class Title Description Source https://policing.umhistorylabs.lsa.umich.edu/s/detroitunderfire/item/269 UNICOM Incident Richard Arnold to Mel Ravitz, November 22, 1971, Box 41, Folder: Police Department (2/3), Part 1, Mel Ravitz Papers, Walter P. Reuther Library, Archives of Labor and Urban Affairs, Wayne State University