Economopoulos T, Psyrri A, Dimopoulos MA, Kalogera-Fountzila A, Pavlidis N, Tsatalas C, Nikolaides C, Mellou S, Xiros N, Fountzilas G. CEOP-21 versus CEOP-14 chemotherapy with or without rituximab for the first-line treatment of patients with aggressive lymphomas: Results of the HE22A99 trial of the hellenic cooperative oncology group. Cancer Journal [Internet]. 2007;13(5):327 - 334.