1. 1) The National Agricultural Statistics Service, Acreage (Published June 28, 2013).
2. 2) http://www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-us.aspx (Accessed 15 Dec., 2013).
3. 3) http://www.weedscience.org (Accessed 15 Dec., 2013).
4. 4) S. A. Culpepper, T. L. Grey, W. K. Vencill, J. M. Kichler, T. M. Webster, S. M. Brown, A. C. York, J. W. Davis and W. W. Hanna: Weed Sci. 54, 620–626 (2006).
5. 5) T. Yoshimura: Kagaku To Seibutsu 50, 552–557 (2012) (in Japanese).