O. Aharony, S. Gubser, J. Maldacena, H. Ooguri, und Y. Oz. (1999)cite arxiv:hep-th/9905111Comment: 261 pages, 42 post-script figures. Please send any comment to jmaldac@fas.harvard.edu. v2: added references and small corrections. v3: minor changes and corrected discussion of SU(3)-invariant supergravity solution.