Bose-Einstein condensation at finite momentum and magnon condensation in thin film ferromagnets J. Hick, F. Sauli, A. Kreisel and P. Kopietz Eur. Phys. J. B, 78 4 (2010) 429-437 Published online: 15 December 2010 DOI: 10.1140/epjb/e2010-10596-7