Wodchis, W. P., Hirdes, J. P., Feeny, D. H. 2003. Health-related quality of life measure based on the minimum data set. International Journal of Technology Assessment in Health Care. 19 (3) 490-506.
Fries, B. E., Nerenz, D. R., Falcon, S. P., Ashcraft, M. L., Lee, C. Z. 1990. A classification system for long-staying psychiatric patients. Medical Care. 28 (4) 311-23.