Frequency of referral and patient characteristics in group practice.
D000293:Adolescent; D000328:Adult; D000368:Aged; D003710:Demography; D005260:Female; D006123:Group Practice; D006801:Humans; D008297:Male; D008875:Middle Aged; D010361:Patients; D012017:Referral and Consultation; D012959:Socioeconomic Factors