R. Wille. Anwendungen der Klassifikation: Datenanalyse und numerische Klassifikation, Indeks-Verlag, Frankfurt, Line diagrams of hierarchical concept systems (engl.\ Übersetzung). Int. Classif. 11 (1984), 77--86.(1984)
A. Nenkova, and R. Passonneau. Proceedings of the Human Language Technology Conference of the North American Chapter of the Association for Computational Linguistics: HLT-NAACL 2004, page 145--152. Boston, Massachusetts, USA, Association for Computational Linguistics, (2004)
H. Nguyen, D. Bozhkov, Z. Ahmadi, N. Nguyen, and T. Doan. Proceedings of the 45th International ACM SIGIR Conference on Research and Development in Information Retrieval, ACM, (July 2022)