1. On two problems concerning linear transformations in Hilbert space;Beurling, Arne;Acta Math.,1948
2. Cambridge Tracts in Mathematics and Mathematical Physics, No. 28;Carathéodory, C.,1952
3. P. L. Duren, Spectral theory of a class of non-self-adjoint infinite matrix operators, doctoral thesis, Massachusetts Institute of Technology, 1960.
4. Analytic functions of class 𝐻_{𝑝};Rudin, Walter;Trans. Amer. Math. Soc.,1955