1. R. L. Anderson, and D. C. Nielsen .1996 .Emergence pattern of five weeds in the Central Great Plains., Weed Technol, 10 :744 –749 .
2. Effect of weed position on yield loss in soyabean and a comparison between relative weed cover and other regression models
3. G. A. Buchanan, and E. R. Burns .1971 .Weed competition in cotton. II. Redroot pigweed and common lambsquarters., Crop Sci, 18 :308 –310 .
4. D. Chikoye, S. F. Weise, and C. J. Swanton .1995 .Influence of common ragweed (Ambrosia artemisifolia) time of emergence and density on white bean (Phaseolus vulgaris)., Weed Sci, 43 :375 –380 .
5. A simple model relating yield loss to weed density