Citation

Thompson: Colorado State University Database. March 13, 1999. University of Colorado. November 27, 2007. 2007 <http://www.ext.colostate.edu/>.

Jill: International Potato Center. 20 May 1999. March 2006. <http://cipotato.org/>.

Thompson, Jim. Home page. June 2004. May 2006. <http://The Organic Gardener.org/>.