Development of Electron Momentum Spectrometer and Study of Helium Structure
Qian Qing, Xu Xiang-Yuan, Tian Jia-He, Zheng Yan-You, Chen Xue-Jun
Acta Phys. -Chim. Sin. . 1994, (05): 385 -386 .  DOI: 10.3866/PKU.WHXB19940501