Problems in the measurement of hospital utilization.
D000367:Age Factors; D004739:England; D005194:Family Practice; D006752:Hospital Planning; D006760:Hospitalization; D006761:Hospitals / Q000706:statistics & numerical data*; D008131:London; D010044:Outpatient Clinics, Hospital / Q000706:statistics & numerical data; D012017:Referral and Consultation; D012737:Sex Factors; D012923:Social Class