Acute upper GI bleeding: did anything change? Time trend analysis of incidence and outcome of acute upper GI bleeding between 1993/1994 and 2000. - van Leerdam,M.E.; Vreeburg,E.M.; Rauws,E.A.; Geraedts,A.A.; Tijssen,J.G.; Reitsma,J.B.; Tytgat,G.N. (Am J Gastroenterol, 2003)