Evolution of surface CNO abundances in massive stars André Maeder, Norbert Przybilla, María-Fernanda Nieva, Cyril Georgy, Georges Meynet, Sylvia Ekström and Patrick Eggenberger A&A, 565 (2014) A39 Published online: 01 May 2014 DOI: 10.1051/0004-6361/201220602