Moussa, Aboubacar, and Mikhail Sergeevich Nikolskii. “An Estimation from Within of the Reachable Set of Nonlinear R. Brockett Integrator With Small Nonlinearity”. Yugoslav Journal of Operations Research, vol. 23, no. 3, Oct. 2013, pp. 355-6, doi:10.2298/YJOR121005026M.