A VLT-ULTRACAM study of the fast optical quasi-periodic oscillations in the polar V834 Centauri M. Mouchet, J.-M. Bonnet-Bidaud, L. Van Box Som, E. Falize, D. A. H. Buckley, H. Breytenbach, R. P. Ashley, T. R. Marsh and V. S. Dhillon A&A, 600 (2017) A53 Published online: 29 March 2017 DOI: 10.1051/0004-6361/201630166