{{Cite journal| doi = 10.1016/j.annemergmed.2021.09.434| issn = 1097-6760 (Electronic) 0196-0644 (Linking)| volume = 79| issue = 4| pages = 354–363| last1 = Nissen| first1 = S. K.| last2 = Candel| first2 = B. G. J.| last3 = Nickel| first3 = C. H.| last4 = de Jonge| first4 = E.| last5 = Ryg| first5 = J.| last6 = Bogh| first6 = S. B.| last7 = de Groot| first7 = B.| last8 = Brabrand| first8 = M.| title = The Impact of Age on Predictive Performance of National Early Warning Score at Arrival to Emergency Departments: Development and External Validation| journal = Ann Emerg Med| date = 2021-11-08| pmid = 34742589}}