Noncommutative spin-1/2 representations J.M. Grimstrup, H. Grosse, E. Kraus, L. Popp, M. Schweda and R. Wulkenhaar Eur. Phys. J. C, 24 3 (2002) 491-494 Published online: 22 May 2002 DOI: 10.1007/s10052-002-0938-6