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Roark, James L.; Johnson, Michael P.; Furstenburg, Francois; Cline Cohen, Patricia; Hartmann, Susan M.; Stage, Sarah; Igo, Sarah E. (2020). "Chapter 19 The City and Its Workers: 1870–1900". The American Promise: A History of the United States (Kindle). Vol. Combined Volume (Value Edition, 8th ed.). Boston, MA: Bedford/St. Martin's. Kindle Locations 14511-14513. ISBN978-1319208929. OCLC1096495503.
Roark, James L.; Johnson, Michael P.; Furstenburg, Francois; Cline Cohen, Patricia; Hartmann, Susan M.; Stage, Sarah; Igo, Sarah E. (2020). "Chapter 19 The City and Its Workers: 1870–1900". The American Promise: A History of the United States (Kindle). Vol. Combined Volume (Value Edition, 8th ed.). Boston, MA: Bedford/St. Martin's. Kindle Locations 14511-14513. ISBN978-1319208929. OCLC1096495503.