1. Vacuum configurations for superstrings
2. For a review, see in: Proceedings of the Superstrings '87, Trieste Spring School, 1987, edited by L. Alvarez-Gaume, M. B. Green, M. Grisaru, R. Jengo, and E. Sezgin (World Scientific, Singapore, 1987).
3. Superstrings with torsion
4. in: Proceedings of Superunification and Extra Dimensions, Turin, 1985, pp. 347-375.
5. Residual supersymmetry of compactified d = 10 supergravity