More Groups
Fewer Groups
Begg, C. B.; Cramer, L. D.; Hoskins, W. J.; Brennan, M. F. JAMA - Journal of the American Medical Association (1998)
Rosenberg, L.; Rao, R. S.; Palmer, J. R.; Strom, B. L.; Stolley, P. D.; Zauber, A. G.; Warshauer, M. E.; Shapiro, S. JAMA - Journal of the American Medical Association (1998)