RT Journal Article SR Electronic T1 Combined estrogen plus progestin may reduce coronary heart disease risk after 5 years of use in postmenopausal women starting treatment within 10 years of menopause JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 69 OP 70 DO 10.1136/ebm1079 VO 15 IS 3 A1 Harman, S. Mitchell YR 2010 UL http://ebm.bmj.com/content/15/3/69.abstract AB