salamou alaikum
I need to these articles as soon as possible :
X. Gonze, Phys. Rev. B 52, 1086 (1995).
X. Gonze, J. C. Charlier, D. C. Allan and M.P. Teter, Phys. Rev. B 50, 13035 (1994).
X. Gonze, Ph. Ghosez and R. W. Godby, Phys. Rev. Lett. 74, 4035 (1995).
May Allah grant you peace all.
Thanks in advance!