RT Journal Article SR Electronic T1 Clinical coding of long COVID in English primary care: a federated analysis of 58 million patient records in situ using OpenSAFELY JF British Journal of General Practice JO Br J Gen Pract FD British Journal of General Practice SP 495 OP 495 DO 10.3399/bjgp21X717449 VO 71 IS 712 YR 2021 UL http://bjgp.org/content/71/712/495.1.abstract AB