Id Url Resource class Title Description Source https://policing.umhistorylabs.lsa.umich.edu/s/crackdowndetroit/item/6257 Guardians Attack Nichols (1973) "Guardians Attack John Nichols," Groundwork, Sept. 1973, The American Radicalism Collection: Part 4: Twentieth-Century Social, Economic, and Environmental Movements, Michigan State University, Political Extremism & Radicalism, http://tinyurl.galegroup.com/tinyurl/8Dgti1