1. Agmon, S., Douglis, A., Nirenberg, L.: Estimates near the boundary for solutions of elliptic partial differential equations satisfying general boundary conditions I. Commun. Pure Appl. Math. 12, 623–727 (1959)
2. Agmon, S., Douglis, A., Nirenberg, L.: Estimates near the boundary for solutions of elliptic partial differential equations satisfying general boundary conditions II. Commun. Pure Appl. Math. 17, 35–92 (1964)
3. Atiyah, M.F., Bott, R.: The index problem for manifolds with boundary, Coll. Differential Analysis. Tata Institute Bombay, Oxford University Press, Oxford (1964)
4. Boutet de Monvel, L.: Boundary problems for pseudo-differential operators. Acta Math. 126, 11–51 (1971)
5. Coriasco, S., Schulze, B.-W.: Edge problems on configurations with model cones of different dimensions. Osaka J. Math. 43, 1–40 (2006)