1. HMO enrollment: Who joins what and why: A review of the literature;Berki;Milbank Memorial Fund Quarterly,1980
2. Health status and health care use by type of private insurance;Blumberg;Milbank Memorial Fund Quarterly,1980
3. A comparison of alternative models of the demand for medical care;Duan,1982
4. Risk differential between medicare beneficiaries enrolled and not enrolled in an HMO;Eggers;Health Care Financing Review,1980
5. Consumer choice health plan;Enthoven;New England Journal of Medicine,1978