Smith, D. (1906). Article 13: Theory of Functions. *History of Modern Mathematics* (Lit2Go Edition). Retrieved July 27, 2016, from http://etc.usf.edu/lit2go/103/history-of-modern-mathematics/1738/article-13-theory-of-functions/

Smith, David Eugene. "Article 13: Theory of Functions." *History of Modern Mathematics*. Lit2Go Edition. 1906. Web. <http://etc.usf.edu/lit2go/103/history-of-modern-mathematics/1738/article-13-theory-of-functions/>. July 27, 2016.

David Eugene Smith, "Article 13: Theory of Functions," *History of Modern Mathematics*, Lit2Go Edition, (1906), accessed July 27, 2016, http://etc.usf.edu/lit2go/103/history-of-modern-mathematics/1738/article-13-theory-of-functions/.