1. Agmon, S. (1962): On the eigenfunctions and on the eigenvalues of general elliptic boundary value problems. Commun. Pure Appl. Math. 15, 119–147.
2. Agmon, S. (1965): On kernels, eigenvalues, and eigenfunctions of operators related to elliptic problems. Commun. Pure Appl. Math. 18, 627–663.
3. Agmon, S., Douglis, A., Nirenberg, L. (1964): Estimates near the boundary for solutions of elliptic partial differential equations satisfying general boundary conditions. II. Commun. Pure Appl. Math. 17, No. 1, 35–92.
4. Agmon, S., Nirenberg, L. (1963): Properties of solutions of ordinary differential equations in Banach spaces. Commun. Pure Appl. Math. 16, No. 2, 121–239.
5. Agranovich, M.S. (1965): Elliptic singular integro-differential operators. Usp. Mat. Nauk 20, No. 5, 3–120.