Frijters, D. H., Achterberg, W. P. 2007. [The ZZP Questionnaire. Reliability of a new resource utilization measure]. Tijdschr Gerontol Geriatr. 38 (4) 165-72.
Björkgren, M. A., Hakkinen, U., Linna, M. 2001. Measuring efficiency of long-term care units in Finland. Health Care Manag Sci. 4 (3) 193-200.
Landi, F., Gambassi, G., Pola, R., Tabaccanti, S., Cavinato, T., Carbonin, P. U., Bernabei, R. 1999. Impact of integrated home care services on hospital use. J Am Geriatr Soc. 47 (12) 1430-4.
Karon, S. L., Sainfort, F., Zimmerman, D. R. 1999. Stability of nursing home quality indicators over time. Medical Care. 37 (6) 570-9.