Found in articles
Theoretical Physics (3rd έκδοση), Dover Publications, ISBN 0-486-65227-0 Kato, Tosio (1995), Perturbation Theory for Linear Operators (2nd έκδοση), Springer-Verlag
Πυκνότητα ηλεκτρονίων
Journal of Quantum Chemistry 95 (6): 877–881. doi:10.1002/qua.10622. Kato, Tosio (1957). «On the eigenfunctions of many-particle systems in quantum mechanics»