Non-trivial extension of the (1+2)-Poincaré algebra and conformal invariance on the boundary of AdS3 I. Benkaddour, A. El Rhalami and E.H. Saidi Eur. Phys. J. C, 21 4 (2001) 735-747 Published online: 15 November 2001 DOI: 10.1007/s100520100769