1. Wainwright, J. (1985). InGalaxies, Axisymmetric Systems and Relativity, M. A. H. MacCallum, ed. (Cambridge University Press, Cambridge), p.288.
2. Hsu, L., and Wainwright, J. (1986).Class. Quantum Grav. 3, 1105.
3. Collins, C. B., and Lang, J. M. (1987).Class. Quantum Grav. 4, 61.
4. Krasiński, A. (1996).Inhomogeneous Cosmological Models, (Cambridge University Press, Cambridge).
5. Hewitt, C. G., Wainwright, J., and Glaum, M. (1991).Class. Quantum Grav. 8, 1505.