On a System of Integrodifferential Equations Occurring in Reactor Dynamics J. LevinJ. Nohel Indiana University Mathematics Journal 1960 text pdf 10.1512/iumj.1960.9.59020 10.1512/iumj.1960.9.59020 en Indiana Univ. Math. J. 9 (1960) 347 - 368 state-of-the-art mathematics http://iumj.org/access/