  We examine the different possible symmetries of the superconducting gap
obtained by solving the Eliashberg equations. We consider an electron-phonon
interaction in a strong coupling scenario. The Coulomb pseudopotential plays
the crucial role of providing the repulsion needed to favour the d-wave
symmetry. But the key parameter that allows very anisotropic solutions even
with very strong coupling is the small angular range of the interaction due to
predominantly electron-phonon forward scattering that is found in the high-Tc
superconductors. We find both s and d-wave solutions whose stability depends
mainly on the angular range of the interaction.
