Acuña, Vicente, Leandro Ishi Soares de Lima, Giuseppe Italiano, Luca Pepè Sciarria, Marie-France Sagot, and Blerina Sinaimeri. 2021. “A Family of Tree-Based Generators for Bubbles in Directed Graphs”. Journal of Graph Algorithms and Applications 25 (1):563-80. https://doi.org/10.7155/jgaa.00572.