1. L.I. Schiff: Quantum Mechanics, 3rd ed. (McGraw-Hill, New York 1968)
2. H.S.W. Massey, E.H.S. Burhop: Electronic and Ionic Impact Phenomena, Vol.! (Clarendon, Oxford 1969) Sect. 6. 3
3. C. Ramsauer: Ann. Phys. 64, 513 (1921)
4. C. Ramsauer: ibid. 66, 545 (1921)
5. C. Erginsoy: Phys. Rev. 79, 1013 (1950)