Five papers were published in these journals in 1926 and 1927: On Laplace's integral equations; On Volterra's integro-functional equation; A new proof of Parseval's identity for trigonometric functions; On Fredholm's integral equations, whose kernels are analytic in a parameter; and The notion of the Green's function in the theory of integro-differential equations.
Limang mga papeles ay nai-publish sa ang mga journal na ito sa 1926 at 1927: Sa kabuuan ng Laplace equation; On Volterra's integro-functional equation; Ang isang bagong patunay ng Parseval ng pagkakakilanlan para sa trigonometriko function; On Fredholm's integral equation, na ang kernels ay analytic sa isang parameter; at Ang pagkaunawa ng Green ang function sa teorya ng integro-kaugalian equation.