by Wang, Xue-Min (雪敏 王), Wu, Wei-Dong (卫东 吴), Wang, Yu-Ying (瑜英 王), Wang, Hai-Ping (海平 王), Ge, Fang-Fang (芳芳 葛), Tang, Yong-Jia (永建 唐), Ju, Xin (新巨)
Published in Chinese physics letters (2011)