1. Johnson, 1972:2121
2. Blau (1964)
3. Turner and Killian, 1972
4. Gerlach and Hines, 1970
5. Andersen, Ronald, and Odin Anderson1979 "Trends in the use of health services." Pp. 371-391 in Howard Freeman, Sol Levine, and LeoReeder (eds.), Handbook of Medical Sociology, 3rd edition, Englewood Cliffs, NJ: PrenticeHall.Andersen3Trends in the use of health services371Handbook of Medical Sociology1979