Structure of a two-dimensional crystal in a Langmuir monolayer : grazing incidence X-ray diffraction and macroscopic properties C. Flament, F. Gallet, F. Graner, M. Goldmann, I. Peterson and A. Renault J. Phys. II France, 4 6 (1994) 1021-1032 DOI: 10.1051/jp2:1994181