Diagnostic yield of endoscopy in patients with abdominal complaints: incremental value of faecal calprotectin on guidelines of appropriateness. - Burri, Emanuel; Manz, Michael; Schroeder, Patricia; Froehlich, Florian; Rossi, Livio; Beglinger, Christoph; Lehmann, Frank Serge (BMC Gastroenterology, 2014)