1. Superstring theory
2. S. Ferrara and B. Zumino, unpublished
3. Conformal invariance in N = 4 supersymmetric Yang-Mills theory
4. P.S. Howe, K.S. Stelle and P.K. Townsend, Nucl. Phys. B, to be published; and in preparation.
5. D. Olive and P. West, Imperial College preprint ICTP/81/82-25.