RT Journal Article SR Electronic T1 The economy of the columnar epithelial cell. JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 2 OP 5 DO 10.1136/gut.10.1.2 VO 10 IS 1 A1 Smyth, D H YR 1969 UL http://gut.bmj.com/content/10/1/2.abstract AB