Fries B.E, Cooney, Jr. L.M.  1985.  Resource utilization groups. A patient classification system for long-term care. Medical Care. 23(2):110-22.

Wodchis W.P, Hirth R.A, Fries B.E.  2007.  Effect of Medicaid payment on rehabilitation care for nursing home residents. Health Care Financ Rev. 28(3):117-29.