The work on Tauberian theorems naturally led him to study the Fourier transform and he published The Fourier Integral, and Certain of Its Applications (1933) and Fourier Transforms in 1934.
Ang trabaho sa Tauberian theorems natural na humantong sa kanya upang pag-aralan ang Fourier-ibang-anyo at siya nai-publish Ang Fourier mahalaga, at tiyak ng kanya Applications (1933) at Fourier Transforms sa 1934.