Root, Michael J. (October 2002). Keller, Fred S. (1899-1996), psychologist and educator. American National Biography Online. Oxford University Press. doi:10.1093/anb/9780198606697.article.1401126.
Root, Michael J. (October 2002). Keller, Fred S. (1899-1996), psychologist and educator. American National Biography Online. Oxford University Press. doi:10.1093/anb/9780198606697.article.1401126.