Optical parameters relevant for High Angular Resolution at Paranal from GSM instrument and surface layer contributionF. Martin, R. Conan, A. Tokovinin, A. Ziad, H. Trinquet, J. Borgnino, A. Agabi and M. SarazinAstron. Astrophys. Suppl. Ser., 144 1 (2000) 39-44DOI: https://doi.org/10.1051/aas:2000197