1-4 of 4 Books

Expansions in eigenfunctions of selfadjoint operators
By Berezanskiĭ, I͡U. M.

Parabolic boundary value problems
By S. D. Ėĭdelʹman,Samuil D. Eidelman,Nicolae V. Zhitarashu

Foundations of modern potential theory
By N. S. Landkof

Classical potential theory and its probabilistic counterpart
By Joseph L. Doob