by Bai, Li-Hua (丽华 白), Hou, Lu-Qiang (路强 侯), Cui, Ting-Ting (婷婷 崔), Liu, Yu-Heng (宇恒 刘), Wang, Yan (燕王), Zhang, Hui-Fang (惠芳 张), Deng, Dong-Mei (冬梅 邓)
Published in Chinese physics letters (01.06.2011)