C. Lintzmayer, F. Miyazawa, and E. Xavier.
" Online Circle and Sphere Packing", in <em>Anais do III Encontro de Teoria da Computação</em>, Natal, 2018, pp. 65-68, doi: <a href="https://doi.org/10.5753/etc.2018.3158">https://doi.org/10.5753/etc.2018.3158</a>.