[1] Yamashita N, Ebisumori K, Nakamura K. Journal of Luminescence(ELSEVIER), 1994, 62: 25.

[2] S.J.Dhoble S J, Gedam S C, Nagpure I M. Mater. Sci., 2008, 43: 3189.

[3] Yamashita Nobuhiko, Ebisumori Kazuo, Nakamura Kaizo. Jpn. J. Appl. Phys., 1993, 32: 3846.

[4] Sun Lingdong, Liu Changhui, Liao Chunsheng. Solid State Communications, 1999, 111: 483.

[5] Aierken Sidike, Keyoumu Niyazi, Zhu Hengjiang. Phys. Chem. Miner., 2009, 36: 119.

[7] Sun Lingdong, Liu Changhui, Liao Chunsheng. J. Mater. Chem., 1999, 9: 1655.

[8] Bol Ageeth A, Ferwerda Joke, Bergwerff Jaap A. Journal of Luminescence, 2002, 99: 325.

[9] Que Wenxiu, Zhou Y, Chan Y C. Applied Physics Letters, 1998, 73: 2727.

[10] Suzuki A, Shionoya S. Phys. Soc. Jpn., 1971, 31: 1455.

[11] Yang Ping, Song Chunfeng, Lu Mengkai. Journal of Physics and Chemistry of Solids(Elsevier), 2002, 63: 639.