Ehlers, Jürgen Geometric Analysis and Gravitation, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;
333043.pdf (Publisher version), 2MB
Ehlers, J. (1993). Contributions to the relativistic mechanics of continuous media. General Relativity and Gravitation, 25(12), 1225-1266. doi:10.1007/BF00759031.