Citation Select	Villanueva C, Colomo A, Bosch A, Concepción M, Hernandez-Gea V, Aracil C, Graupera I, Poca M, Alvarez-Urturi C, Gordillo J, Guarner-Argente C, Santaló M, Muñiz E, Guarner C Transfusion strategies for acute upper gastrointestinal bleeding N Engl J Med. 2013 Jan 3;368(1):11-21