The Pioneer anomaly. Turyshev, Slava G., Toth, Viktor T. (2010) Living Reviews in Relativity [electronic only]
The thermodynamics of black holes. Wald, Robert M. (2001) Living Reviews in Relativity [electronic only]
Variation of the equator due to a highly inclined and eccentric disturber. Do Nascimento, Clair, Yokoyama, Tadashi (2009) Mathematical Problems in Engineering