R. Sampaio, G. Sobral, and Y. Wakabayashi.
" Minimum Density of Identifying Codes of Hexagonal Grids with a Finite Number of Rows", in <em>Anais do VII Encontro de Teoria da Computação</em>, Niterói, 2022, pp. 145-148, doi: <a href="https://doi.org/10.5753/etc.2022.223348">https://doi.org/10.5753/etc.2022.223348</a>.