Boundary value problems for Waldenfels operators Thomas RunstAbdellah Youssfi 35J2547G1047G2046E3547D0747H30Degenerate boundary value problemsintegral-differential operatorsSobolev spaces We study boundary value problems for second-order elliptic integro-differential operators. We prove existence and uniqueness in the framework of Bessel potential spaces. Indiana University Mathematics Journal 2005 text pdf 10.1512/iumj.2005.54.2474 10.1512/iumj.2005.54.2474 en Indiana Univ. Math. J. 54 (2005) 237 - 256 state-of-the-art mathematics http://iumj.org/access/