The discrete variational principle and the first integrals of Birkhoff systems

张宏彬, 陈立群, 顾书龙, 柳传长

Zhang Hong-Bin(张宏彬), Chen Li-Qun(陈立群), Gu Shu-Long(顾书龙), and Liu Chuan-Zhang(柳传长)

中国物理B . 2007, (3): 582 -587 . DOI: 10.1088/1009-1963/16/3/004