Hertz, Alain, Romain Montagné, and François Gagnon. “Constructive Algorithms for the Partial Directed Weighted Improper Coloring Problem”. Journal of Graph Algorithms and Applications 20, no. 2 (February 1, 2016): 159–188. Accessed June 30, 2024. https://jgaa.info/index.php/jgaa/article/view/paper389.