Internal energy and gravitation
John O'Hanlon, Peter Rastall, K -K Lam · Journal of physics. A, Proceedings of the Physical Society. General · 1968
A previous theory of the interaction of an ideal fluid with the gravitational field, as given by Rastall in 1968, is modified. It is now assumed that the natural internal energy per unit mass of the fluid is a function of the natural pressure and density.