RT Journal Article SR Electronic T1 Treatment of chronic constipation with lactulose syrup: results of a double-blind study. JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 84 OP 86 DO 10.1136/gut.9.1.84 VO 9 IS 1 A1 A Wesselius-De Casparis A1 S Braadbaart A1 G E Bergh-Bohlken A1 M Mimica YR 1968 UL http://gut.bmj.com/content/9/1/84.abstract AB