RT Journal Article SR Electronic T1 Combined pH-impedance testing for reflux: current state of play and future challenges JF Frontline Gastroenterology JO Frontline Gastroenterol FD BMJ Publishing Group Ltd SP flgastro-2017-100840 DO 10.1136/flgastro-2017-100840 A1 Santosh Sanagapalli A1 Rami Sweis YR 2017 UL http://fg.bmj.com/content/early/2017/04/21/flgastro-2017-100840.abstract AB