[1] CORNELL UNIV MED COLL, NEW YORK, NY USA
[2] HARVARD UNIV, SCH MED, BOSTON, MA 02115 USA
[3] HARVARD UNIV, SCH PUBL HLTH, BOSTON, MA 02115 USA
[4] VET ADM MED CTR, GASTROENTEROL SECT, MINNEAPOLIS, MN USA
[5] UNIV CALIF SAN DIEGO, LA JOLLA, CA 92093 USA
[6] JOHNS HOPKINS UNIV, HEREDITARY COLON CANC & POLYPOSIS CLIN, BALTIMORE, MD USA
[7] MED COLL PENN & HAHNEMANN UNIV, DIV GASTROINTESTINAL RADIOL, PHILADELPHIA, PA 19102 USA
[8] BRITISH MED JOURNAL, LONDON, ENGLAND
[9] ONCOL WISCONSIN SC, MILWAUKEE, WI USA
[10] DANA FARBER CANC INST, DEPT MED, BOSTON, MA 02115 USA
[11] MILLER ECON CONSULTING, ALEXANDRIA, VA USA
[12] UNIV TEXAS, HLTH SCI CTR, SAN ANTONIO, TX 78285 USA
[13] JOHNS HOPKINS UNIV, SCH NURSING, BALTIMORE, MD USA
[14] PENN STATE UNIV, COLL MED, MILTON S HERSHEY MED CTR, ALLENTOWN, PA USA
[15] LEHIGH VALLEY HOSP CTR, ALLENTOWN, PA 18102 USA
[16] COLUMBIA UNIV, SCH PUBL HLTH, NEW YORK, NY USA
[17] AMER GASTROENTEROL ASSOC, BETHESDA, MD USA
[18] LASER CTR MARYLAND, SEVERNA PK, MD USA
[19] VIRGINIA COMMONWEALTH UNIV, MED COLL VIRGINIA, RICHMOND, VA 23298 USA
[20] UNIV MASSACHUSETTS, SCH MED, WORCESTER, MA 01605 USA