More Groups
Fewer Groups
More People
Fewer People
Panageas, K. S.; Schrag, D.; Riedel, E.; Bach, P. B.; Begg, C. B. Annals of Internal Medicine (2003)
Levenson, D.; Gulec, S.; Sonenberg, M.; Lai, E.; Goldsmith, S. J.; Larson, S. M. Annals of Internal Medicine (1994)