{{Cite journal| doi = 10.1148/radiology.210.3.r99fe54639| issn = 0033-8419 (Print) 0033-8419 (Linking)| volume = 210| issue = 3| pages = 639–43| last1 = Vermeulen| first1 = B.| last2 = Morabia| first2 = A.| last3 = Unger| first3 = P. F.| last4 = Goehring| first4 = C.| last5 = Grangier| first5 = C.| last6 = Skljarov| first6 = I.| last7 = Terrier| first7 = F.| title = Acute appendicitis: influence of early pain relief on the accuracy of clinical and US findings in the decision to operate--a randomized trial| journal = Radiology| date = 1999-04-20| pmid = 10207461}}