Bjorkgren M.A, Finne-Soveri U.H, Sairaala K.  1995.  RUG: A classification system for institutional long-term care.. Stakes. 4:39-42.

Bjorkgren M.A, Hakkinen U., Brommels M.  1999.  RUG-III classification and need of care in the care register systems in institutional long-term care.. Terveystaloustieteen Paiva. 45:41-43.

Hakkinen U., Noro A, Finne-Soveri H., Kaupunki A, Bjorkgren M.A, Instituut C.  2000.  RAI system in the economical evaluation of the elderly care.. 45:37-39.