1. The Classical Moment Problem;Akhiezer,1965
2. Theory of Linear Operators in Hilbert Space;Akhiezer,1961
3. The Birman–Krein–Vishik theory of self-adjoint extensions of semibounded operators;Alonso;J. Operator Theory,1980
4. Padé Approximants;Baker,1996
5. Linear Operators, II. Spectral Theory;Dunford,1963