RT Journal Article SR Electronic T1 Risk of venous thromboembolism with oral contraceptives JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E1278 OP E1279 DO 10.1503/cmaj.111614 VO 183 IS 18 A1 Solymoss, Susan YR 2011 UL http://www.cmaj.ca/content/183/18/E1278.abstract