Pakpahan, R.; G. Maffett, M.; Doortua, D.; Maswan, M.; Lubis, J. FACTORS INFLUENCING THE OCCURRENCE OF RHEUMATOID ARTHRITIS (RA) IN THE ELDERLY IN THE REGIONUPTDJAVA COMMUNITY HEALTH CENTER SIMALUNGUN DISTRICT YEAR 2020. IHERT 2020, 2, 111-126.