1. Long wavelength optical phonons in mixed crystals
2. G. Burns,Solid State Physics(Academic, Orlando, 1985), p. 458.
3. G. Burns,Solid State Physics(Academic, Orlando, 1985), p. 469.
4. Infrared reflectivity studies of gax in1-x asy p1-y quaternary compounds
5. M. Born and E. Wolf,Principles of Optics, 5th. ed. (Pergamon, New York, 1975), p. 628.