The elderly in Białystok. Part I. Assumption, organization and progress of the study.
D000368:Aged; D005260:Female; D006262:Health; D006299:Health Services for the Aged / Q000706:statistics & numerical data*; D006304:Health Status; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D011044:Poland; D012494:Sampling Studies; D011795:Surveys and Questionnaires