Maintenance work on the ZORA database servers is scheduled for Thursday 25th July 2019 from 19:00-20:00. During this period ZORA and JDB will not be available. Thank you for your understanding.
Frei, A; Williams, K; Vetsch, A; Dobbels, F; Jacobs, L; Rudell, K; Puhan, M A (2011). A comprehensive systematic review of the development process of 104 patient-reported outcomes (PROs) for physical activity in chronically ill and elderly people. Health and Quality of Life Outcomes, 9:116.
Gimeno-Santos, E; Frei, A; Dobbels, F; Rudell, K; Puhan, M A; Garcia-Aymerich, J (2011). Validity of instruments to measure physical activity may be questionable due to a lack of conceptual frameworks: a systematic review. Health and Quality of Life Outcomes, 9:86.