Celestial Mechanics in the XXIst century – challenges Vivian M. Gomes, Antônio F.B.A. Prado, Cristiano F. de Melo, Elbert E.N. Macau and Othon C. Winter Eur. Phys. J. Special Topics, 229 8 (2020) 1373-1377 Published online: 29 May 2020 DOI: 10.1140/epjst/e2020-000068-6