Casimir effect for gauge fields in spaces with negative constant curvature A. A. Bytsenko, M. E. X. Guimarães and V. S. Mendes Eur. Phys. J. C, 39 2 (2005) 249-252 Published online: 15 February 2005 DOI: 10.1140/epjc/s2004-02080-3