van Dam C.S, Trappenburg M.C, Wee M.M ter, Hoogendijk E.O, de Vet H.C, Smulders Y.M, Nanayakkara P.W, Muller M., Peters M.J.  2021.  The Accuracy of Four Frequently Used Frailty Instruments for the Prediction of Adverse Health Outcomes Among Older Adults at Two Dutch Emergency Departments: Findings of the AmsterGEM Study. Annals of Emergency Medicine. 78(4):538-548.