The Role of Initial Laparotomy and Second-Look Surgery in the Treatment of Abdominal B-Cell Non-Hodgkin's Lymphoma of Childhood. A Report of the BFM Group*, ** - Reiter, A; Zimmermann, W; Zimmermann, M; Schweinitz, D von; Riehm, H; Mildenberger, H (European Journal of Pediatric Surgery, 1994)