Extended dx2 - y2-wave superconductivity. Flat nodes in the gap and the low-temperature asymptotic properties of high-Tc superconductorsG. G.N. Angilella, A. Sudbø and R. PucciEur. Phys. J. B, 15 2 (2000) 269-275DOI: https://doi.org/10.1007/s100510051125