New approach to the superconductivity problem
  In this work, a question is tackled concerning the formation of a superconducting condensate in an earlier proposed model of "elastic jelly", in which phonons of the ion system play the part of initiating ones. It was shown that in distinction from the BCS theory, the momenta of forming electron pairs are different from zero. This fact changes the pattern of the description of the superconductivity phenomenon in the proposed model. First, the gap in the one-electron spectrum appears due to the effect of a "mean field" on the energy of electron state from the side of occupied states, the nearest neighbors over the momenta grid. Second, the condensate is formed by electron states with energies below that of the gap edge, this is why the Fermi-condensation arises in the system. Third, anomalous expectation values are strictly equal to zero in the proposed model. 
I.M.Yurin and V.B.Kalinin