TY - JOUR T1 - Canadian National Breast Screening Study JF - Canadian Medical Association Journal JO - CMAJ SP - 876 LP - 877 VL - 148 IS - 6 AU - J. J. Caro AU - J. A. O'Brien AU - S. C. Hartz Y1 - 1993/03/15 UR - http://www.cmaj.ca/content/148/6/876.abstract ER -