Silletti AM, Knapp AK. Responses of the co-dominant grassland species Andropogon gerardii and Sorghastrum nutans to long-term manipulations of nitrogen and water. American Midland Naturalist. 2001;145:159 -167. doi:10.1674/0003-0031(2001)145[0159:ROTCGS]2.0.CO;2.