Psyrri, Amanda Kalogera-Fountzila, Anna Dimopoulos, Meletios A Pavlidis, Nicholas Tsatalas, Costas Nikolaides, Costas Mellou, Sofia Xiros, Nikolaos Kountourakis, Panteleimon Economopoulos, Theofanis, Three-weekly or 2-weekly CEOP chemotherapy with or without mabthera for the treatment of patients with aggressive non-Hodgkin's lymphoma: Results from a randomized trial of the hellenic cooperative oncology group, 196--197, 2006,