Elastic anomalies at structural phase transitions : a consistent perturbation theory. II. Two-component order parameter including the case of incommensurate phase N. I. Lebedev, A.P. Levanyuk, S. A. Minyukov et M. ValladeJ. Phys. I France, 2 12 (1992) 2293-2297DOI: https://doi.org/10.1051/jp1:1992281
