Assessment of risk-independent follow-up to detect asymptomatic recurrence after curative resection of colorectal cancer - Zitt, Matthias; Mühlmann, Gilbert; Weiss, Helmut; Kafka-Ritsch, Reinhold; Oberwalder, Michael; Kirchmayr, Werner; Margreiter, Raimund; Öfner, Dietmar; Klaus, Alexander (Langenbeck's Archives of Surgery, 2006)