1. Calculus of Finite Differences;Gel'fond,1971
2. Convergence Properties of Recurrence Sequences;Kooman;Doctoral Dissertation,1989
3. The support of measures associated with orthogonal polynomials and the spectra of the related self adjoint operators;Máté,1988
4. The Calculus of Finite Differences;Milne-Thomson,1933
5. Vorlesungen über Differenzenrechnung;Nörlund,1924