On a Difference-Integral Equation P. AnselonH. Bueckner Indiana University Mathematics Journal 1962 text pdf 10.1512/iumj.1962.11.11005 10.1512/iumj.1962.11.11005 en Indiana Univ. Math. J. 11 (1962) 81 - 100 state-of-the-art mathematics http://iumj.org/access/