Calvo E, Amarillas L, Mateos M A, Orradre J L, Gilsanz G, Alvarez-Sala J L, Espinos D
Department of Internal Medicine, Hospital Universitario San Carlos, School of Medicine, Complutense University, Madrid, Spain.
Dig Dis Sci. 1996 Mar;41(3):591-3. doi: 10.1007/BF02282346.