The MiMeS survey of magnetism in massive stars: CNO surface abundances of Galactic O starsF. Martins, A. Hervé, J.-C. Bouret, W. Marcolino, G. A. Wade, C. Neiner, E. Alecian, J. Grunhut, V. Petit and the MiMeS collaborationA&A, 575 (2015) A34DOI: https://doi.org/10.1051/0004-6361/201425173