1. Seminar on the Embedding Problem Introduction
2. H. F. Goenner, inGeneral Relativity and Gravitation, edited by A. Held (Plenum, New York, 1980), Vol. 1.
3. D. Kramer, H. Stephani, M. MacCallum, and E. Herlt, Exact solutions of Einstein’s field equations (Cambridge University Press, Cambridge, 1980).
4. Empty space-times of embedding class two
5. Type D empty space-times of embedding class 2