Nemat Abazari and  Ilgin Sager,  Planning Rigid Body Motions and Optimal Control Problem on Lie Group SO(2, 1).   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    April 2010, vol. 40(4). 468 - 472
    [viewed 14 December 2019]. Available from: https://publications.waset.org/pdf/12800.