Existence, Uniqueness and Stability of Solutions of Systems of Nonlinear Difference-Differential Equations W. Miranker Indiana University Mathematics Journal 1962 text pdf 10.1512/iumj.1962.11.11006 10.1512/iumj.1962.11.11006 en Indiana Univ. Math. J. 11 (1962) 101 - 107 state-of-the-art mathematics http://iumj.org/access/