For Copeland’s biography I drew on Copeland’s Cure: Homeopathy and the War between Conventional and Alternative Medicine by Natalie S. Robins (Knopf, 2005) and for the 1918-19 pandemic I used The Great Influenza: The Story of the Deadliest Pandemic in History by John M. Barry (Penguin Books, 2018) and American Influenza Epidemic of 1918 - 1919: A Digital Encyclopedia. The epidemiological study cited is Howard Markel et al., "Nonpharmaceutical Interventions Implemented by US Cities During the 1918-1919 Influenza Pandemic" (Journal of the American Medical Association 2007; 298 (6): 644-654). Copeland’s major interview with The New York Times was published as "Epidemic Lessons Against Next Time: Dr. Copeland Tells Why New York Got Off Easier Than Other Cities—Pays Tribute to Predecessors," November 17, 1918, p. 42. The additional quotation from Copeland is from "Grip Wanes, But Copeland Urges Care," New York American, October 25, 1918, p. 9.