On the Pressures and the Flux of Energy in a Gas according to Maxwell's Kinetic Theory, I E. IkenberryC. Truesdell Indiana University Mathematics Journal 1956 text pdf 10.1512/iumj.1956.5.55001 10.1512/iumj.1956.5.55001 en Indiana Univ. Math. J. 5 (1956) 1 - 54 state-of-the-art mathematics http://iumj.org/access/