Space/time non-commutative field theories and causality H. Bozkaya, P. Fischer, H. Grosse, M. Pitschmann, V. Putz, M. Schweda and R. Wulkenhaar Eur. Phys. J. C, 29 1 (2003) 133-141 Published online: 23 May 2003 DOI: 10.1140/epjc/s2003-01210-9