TY - STAND AU - M. Gulliford AU - T. van Staa AU - L. McDermott AU - G. McCann AU - J. Charlton AU - A. Dregan BT - Trials DO - 10.1186/1745-6215-15-220 PY - 2014 EP - 220 T2 - Trials TI - Cluster randomized trials utilizing primary care electronic health records: methodological issues in design, conduct, and analysis (eCRT Study) VL - 15 SN - 1745-6215 ER -