Comparative demographic profiles: voluntary and paid blood donors.
D000328:Adult; D001782:Blood Donors; D003710:Demography; D004651:Employment; D005260:Female; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009790:Occupations; D012959:Socioeconomic Factors