The photospheric solar oxygen project - IV. 3D-NLTE investigation of the 777 nm triplet lines M. Steffen, D. Prakapavičius, E. Caffau, H.-G. Ludwig, P. Bonifacio, R. Cayrel, A. Kučinskas and W. C. Livingston A&A, 583 (2015) A57 Published online: 27 October 2015 DOI: 10.1051/0004-6361/201526406