RT Journal Article SR Electronic T1 The power to certify JF British Journal of General Practice JO Br J Gen Pract FD British Journal of General Practice SP 517 OP 517 DO 10.3399/bjgp21X717617 VO 71 IS 712 A1 Tim Senior YR 2021 UL http://bjgp.org/content/71/712/517.abstract AB