Omeprazole does not reduce gastroesophageal reflux: new insights using multichannel intraluminal impedance technology. - Tamhankar,A.P.; Peters,J.H.; Portale,G.; Hsieh,C.C.; Hagen,J.A.; Bremner,C.G.; DeMeester,T.R. (J Gastrointest Surg, 2004)