Non-commutative Lorentz symmetry and the origin of the Seiberg–Witten map A.A. Bichl, J.M. Grimstrup, H. Grosse, E. Kraus, L. Popp, M. Schweda and R. Wulkenhaar Eur. Phys. J. C, 24 1 (2002) 165-176 Published online: 15 May 2002 DOI: 10.1007/s100520100857