1. P. Podleś, SL. Woronowicz: Mittag-Leffler Institute Report No. 20, 1988/1989
2. U. Carow-Watamura, M. Schlieker, M. Scholl, S. Watamura: Z. Phys. C — Particles and Fields 48 (1990) 159–165; preprint KA-THEP-1990-14, to be published in Int. Mod. Phys. A
3. W.B. Schmidke, J Wess, B. Zumino: forthcoming paper
4. J Wess, B. Zumino: Nucl. Phys. B (Proc. Suppl.) 18B (1990) 302
5. J. Wess: Talk given at Third Centenary Celebrations of the Mathematische Gesellschaft, March 1990, based on work with B. Zumino. Preprint KA-THEP-1990-22 (1990)