Aboulker P, Bousquet N, de Verclos R. Chordal Directed Graphs Are Not $\chi$-Bounded. Electron. J. Combin. [Internet]. 2022May6 [cited 2026Apr.4];29(2):P2.17. Available from: https://www.combinatorics.org/ojs/index.php/eljc/article/view/v29i2p17