limite de Fermi-Teller
1977 / [Notes and Discussions] Historical perspective on minimum dipole moment required to bind an electron / Kenneth Fox / American Journal of Physics 45 (1977) p. 871 [doi]
2007 / Critical dipoles in one, two, and three dimensions / Kevin Connolly ; David J. Griffiths / American Journal of Physics 75 (2007) p. 524 [doi]