Publisher
Springer Science and Business Media LLC
Reference15 articles.
1. A. Weinstein andW. Stenger:Methods of Intermediate Problems for Eigenvalues (Academic Press, New York, N.Y., 1972).
2. C. S. Sharma andS. SriRankanathan:J. Phys. A,8, 1853 (1975).
3. H. Poincaré:Am. J. Math.,12, 211 (1890).
4. E. A. Hylleraas andB. Undheim:Z. Phys.,65, 759 (1930).
5. J. B. Diaz andF. T. Metcalf:J. Math. Mech.,17, 623 (1968).