1. TUNNELING MEASUREMENTS OF THE ENERGY GAP IN HIGH-Tc SUPERCONDUCTORS
2. Introduction to Superconductivity;Tinkham,1980
3. J.R. Schrieffer in Theory of Superconductivity Addison-Wesley Publishing Co., 1964
4. P.G. DeGennes in Superconductivity of Mefals and Alloys Addison-Wesley Publishing Co., 1989
5. Energy Gap in Superconductors Measured by Electron Tunneling