Smith, D. (1906). Article 6: Theory of Equations. *History of Modern Mathematics* (Lit2Go Edition). Retrieved April 18, 2015, from http://etc.usf.edu/lit2go/103/history-of-modern-mathematics/1731/article-6-theory-of-equations/

Smith, David Eugene. "Article 6: Theory of Equations." *History of Modern Mathematics*. Lit2Go Edition. 1906. Web. <http://etc.usf.edu/lit2go/103/history-of-modern-mathematics/1731/article-6-theory-of-equations/>. April 18, 2015.

David Eugene Smith, "Article 6: Theory of Equations," *History of Modern Mathematics*, Lit2Go Edition, (1906), accessed April 18, 2015, http://etc.usf.edu/lit2go/103/history-of-modern-mathematics/1731/article-6-theory-of-equations/.