Connell RK, O'Connor R, Nippert JB, Blair JM. Spatial variation in soil microbial processes as a result of woody encroachment depends on shrub size in tallgrass prairie. Plant and Soil. 2021;460:359 - 373. doi:10.1007/s11104-020-04813-9.

O'Connor R. Drivers, mechanisms, and thresholds of wood encroachment in mesic grasslands. Department of Biology. 2019;PhD Dissertation. Available at: https://krex.k-state.edu/dspace/handle/2097/40021.