THE METHODOLOGY OF COMPLEX SOCIAL HYGIENIC INVESTIGATION OF VARIOUS GROUPS OF POPULATION AND FAMILIES (IN MEMORIAM OF PROFESSOR O. V. GRININA) Article Kicha D.I., Nechaev V.S., Stepanova S.M. Problemy sotsial'noi gigieny, zdravookhraneniia i istorii meditsiny. Акционерное общество "Шико". Vol. 27. 2019. P. 328-332