PT - JOURNAL ARTICLE ED - , TI - Clusters. DP - 1970 Mar 01 TA - The Journal of the Royal College of General Practitioners PG - 123--124 VI - 19 IP - 92 4099 - http://bjgp.org/content/19/92/123.short 4100 - http://bjgp.org/content/19/92/123.full SO - J R Coll Gen Pract1970 Mar 01; 19