1. I.Giaever: Phys. Rev. Lett.5, 464 (1960)
2. G.M.Eliashberg: JETP11, 696 (1960)
3. W.L.McMillan, J.M.Rowell: InSuperconductivity, ed. by R.D.Parks (Marcell Dekker, New York 1969)
4. J.M.Rowell, W.L.McMillan, R.C.Dynes: A Tabulation of the Electron-Phonon Interaction in Superconducting Metals and Alloys (unpublished)
5. W.L.McMillan: Phys. Rev.167, 331 (1968)