More Groups
Fewer Groups
Begg, C. B. Controlled Clinical Trials (2000)
Houston, C.; Frankel, J.; Quinlivan, S.; Gallina, E.; Berkery, R.; Begg, C. Controlled Clinical Trials (1992)
Wu, D.; Begg, C.; Houston, C.; Miller, E. Controlled Clinical Trials (1992)
Begg, C. B. Controlled Clinical Trials (1990)