Financing of health services : report of a WHO study group The Uses of epidemiology in the study of the elderly : report of a WHO scientific group on the epidemiology of Aging The Role of health centres in the development of urban health systems : report of a WHO Study Group on Primary Health Care in urban Areas Research in human reproduction : strengthening of resources in developing countries : report of a WHO study group Research for the reorientation of national health systems : report of a WHO study group WHO Study Group on Epidemiology of Leprosy in Relation to Control : report of a WHO study groupImproving performance of health centres in district health systems: report of a WHO Study GroupMental health care in developing countries : a critical appraisal of research findings : report of a WHO study groupCommunity involvement in health development : challenging health services : report of a WHO Study GroupThe hospital in rural and urban districts : report of a WHO Study Group on the functions of hospitals at the first referral level