Greene EJ. A SAS Macro for Covariate-Constrained Randomization of General Cluster-Randomized and Unstratified Designs. J. Stat. Soft. [Internet]. 2017 Apr. 3 [cited 2024 Nov. 24];77(1):1-20. Available from: https://www.jstatsoft.org/index.php/jss/article/view/v077c01