AU - Covinsky KE TI - The incremental nature of clinical research: Comment on “the association of aspirin use with age-related macular degeneration” PT - JOUR DP - 2013 TA - JAMA Internal Medicine pages = {266}, VI - 173 IP - 4 AID - 10.1001/jamainternmed.2013.2790 [doi] 4100 - http://dx.doi.org/10.1001/jamainternmed.2013.2790 SO - JAMA Internal Medicine February 25, 2013 173(4):266