Norris MD, Blair JM, Johnson LC. Altered ecosystem nitrogen dynamics as a consequence of land cover change in tallgrass prairie. American Midland Naturalist. 2007;158:432 -445. doi:10.1674/0003-0031(2007)158[432:AENDAA]2.0.CO;2.

Hoch GA, Briggs JM, Johnson LC. Assessing the rate, mechanism and consequences of conversion of tallgrass prairie to Juniperus virginiana forest. Ecosystems. 2002;5:578 -586. doi:10.1007/s10021-002-0187-4.

Norris MD, Blair JM, Johnson LC, McKane RB. Assessing changes in biomass, productivity, and C and N stores following Juniperus virginiana  forest expansion into tallgrass prairie. Canadian Journal of Forest Research. 2001;31:1940 -1946. doi:10.1139/x01-132.