Zhang, Y., J. S. Preisser, F. Li, E. L. Turner, and P. J. Rathouz. “CRTFASTGEEPWR: A SAS Macro for Power of Generalized Estimating Equations Analysis of Multi-Period Cluster Randomized Trials With Application to Stepped Wedge Designs”. Journal of Statistical Software, Code Snippets, vol. 108, no. 1, Mar. 2024, pp. 1-27, doi:10.18637/jss.v108.c01.