I saw a reference in Jackson's "Classical Electrodynamics" book for Stakgold's book on "Boundary Value Problems and Green's Functions" as a reference for Green's functions. The text is sort of clear, although I have had to go through the material on distributions several times in order to even get a faint understanding, but when I try to do the problems, the level of mathematical expertise required for them is far beyond what I have. I'm not even sure where to begin as far as figuring out what I need to learn in order to get a grasp of the problems.
If anyone is familiar with Stakgold's book and has had some success with it, can you tell me what prerequisites are needed to get through it? Especially the problems that have to do with the chapter on distributions, which is about as far as I got.