Wolf-Rayet stars in the Small Magellanic Cloud - I. Analysis of the single WN stars R. Hainich, D. Pasemann, H. Todt, T. Shenar, A. Sander and W.-R. Hamann A&A, 581 (2015) A21 Published online: 26 August 2015 DOI: 10.1051/0004-6361/201526241