Wagler, Annegret (2001), "Critical and anticritical edges in perfect graphs", Graph-Theoretic Concepts in Computer Science: 27th International Workshop, WG 2001, Boltenhagen, Germany, June 14–16, 2001, Proceedings, Lecture Notes in Computer Science, vol. 2204, Berlin: Springer, pp. 317–327, doi:10.1007/3-540-45477-2_29, MR1905643.
Wagler, Annegret (2001), "Critical and anticritical edges in perfect graphs", Graph-Theoretic Concepts in Computer Science: 27th International Workshop, WG 2001, Boltenhagen, Germany, June 14–16, 2001, Proceedings, Lecture Notes in Computer Science, vol. 2204, Berlin: Springer, pp. 317–327, doi:10.1007/3-540-45477-2_29, MR1905643.