http://www.csrees.usda.gov/nea/plants/in_focus/ptbreeding_if_study.html.
http://cuke.hort.ncsu.edu/cucurbit/wehner/741/hs741hist.html – History of plant breeding.
http://www.cast-science.org/file.cfm/media/products/digitalproducts/CAST_IP57_Plant_Breeding_and_Geneti_3AD033F3C1763.pdf
