G. E. Tsydynzhapov, A. F. Shevchun, M. R. Trunin, V. N. Zverev, D. V. Shovkun, N. V. Barkovskiy, and L. A. Klinkova "Observation of a Transition from BCS to HTSC-like Superconductivity in Ba 1-x K x BiO 3 Single Crystals " JETP Letters, 83 , 405 (2006) . This is well known that the electron concentration in superconductor K x Ba 1-x BiO 3 diminishes together with the critical temperature T c when the potassium doping x increases above x=0.35. ...