Allore, Heather G., Yuming Ning, Cynthia A. Brandt, and Joseph L. Goulet. 2013. “Accounting for the Hierarchical Structure in Veterans Health Administration Data: Differences in Healthcare Utilization Between Men and Women Veterans”. International Journal of Statistics in Medical Research 2 (2):94-103. https://doi.org/10.6000/1929-6029.2013.02.02.03.