Path integral for relativistic oscillators: model of the Klein–Gordon particle in AdS space M.T. Chefrour, F. Benamira and L. Guechi Eur. Phys. J. C, 28 3 (2003) 395-403 Published online: 24 March 2003 DOI: 10.1140/epjc/s2003-01164-x