1982 interview with Judy Harris, republished in "Aunt Bessie's How to Survive a Day Job While Pursuing the Creative Life" edited by Joel Eisenbergy, Topos Books, (p. 67), 2005.
John George Nicolay (2008). “A Short Life of Abraham Lincoln: Condensed from Nicolay & Hay's Abraham Lincoln: a History: Easyread Large Edition”, p.44, ReadHowYouWant.com