Journal of Clinical Epidemiology
Journal of Clinical Epidemiology > 2007 > 60 > 4 > 356-360
Journal of Clinical Epidemiology > 2007 > 60 > 5 > 440-447
Journal of Clinical Epidemiology > 2007 > 60 > 4 > 356-360
Journal of Clinical Epidemiology > 2007 > 60 > 5 > 440-447