Comments on gap anisotropy and nodal constant Fermi velocity in a   superconductor, BSCCO
  On the basis of both the inhomogeneity of a superconductor, BSCCO-2212, and the effect of measurement, we reveal that an anomalously large gap anisotropy known as evidence of dx2-y2-wave symmetry [Phys. Rev. Lett. 70 (1993) 1553] is not intrinsic, and that the constant Fermi velocity at node as an unsolved problem [Nature 423 (2003) 398] is due to the dx2-y2-wave insulator-metal transition. 
Hyun-tak Kim, Bong-jun Kim, Kwang-yong Kang