Wang Xiao-Xiao, Zhang Mei-Ling, Han Yue-Lin, Jia Li-Qun. Mei symmetry and Mei conserved quantity of Nielsen equation in a dynamical system of the relative motion with nonholonomic constraint of Chetaev's typeJ. Acta Physica Sinica, 2012, 61(20): 200203. DOI: 10.7498/aps.61.200203