Optical and paramagnetic properties of titanium centres in ZnS J. Dziesiaty, M. U. Lehr, P. Peka, A. Klimakow, S. Müller and H.-J. Schulz Eur. Phys. J. B, 4 3 (1998) 269-277 Published online: 15 August 1998 DOI: 10.1007/s100510050379