1. Rendall, A.D.: Solutions of the Einstein equations with matter. In: Francaviglia, M., Longhi, G., Lusanna, L., Sorace, E. (eds.) Proceedings of the 14th International Conference on General Relativity and Gravitation, pp. 313-335. World Scientifc (1997)
2. Nungesser, E., Andersson, L., Bose, S., Coley, A.A.: Gen. Rel. Grav. 46, 1628 (2013)
3. Andreasson, H.: Liv. Rev. Relativ. 14, 4 (2011)
4. Calogero, S., Heinzle, J.M.: SIAM J. Appl. Dyn. Syst. 9, 1244 (2010)
5. Heinzle, J.M., Uggla, C.: Class. Quant. Grav. 23, 3463 (2006)