Bedside Endosonography and Endosonography-Guided Fine-Needle Aspiration in Critically III Patients: A Way out of the Deadlock? - Fritscher-Ravens, A.; Sriram, P. V. J.; Pothman, W. P.; Füllekrug, B.; Jäckle, S.; Thonke, F.; Soehendra, N. (Endoscopy, 2000)