SOLID STATE IONICS, vol. 111, no. 1-2, page. 1 - 7, 1998-08
SOLID STATE COMMUNICATIONS, vol. 108, no. 9, page. 655 - 660, 1998-01
JOURNAL OF RAMAN SPECTROSCOPY, vol. 30, no. 7, page. 497 - 500, 1999-07