Cited several times. E.g. 1. Marco Kuhlmann & Joakim Nivre: Mildly non-projective dependency structures. In the Proceedings of the COLING/ACL on Main conference poster sessions, p. 507--514. In series COLING-ACL '06. Sydney, Australia, 2006. 2. Carlos Gómez-Rodriguez and Joakim Nivre: A transition-based for 2-Planar Dependency Structures. In Proceedings of the 48th Annual Meeting of the Association for Computational Linguistics, pages 1492--1501, Uppsala, Sweden, 11-16 July 2010. ACL 3. Marco Kuhlmann. Dependency Structures and Lexicalized Grammars. An Algebraic Approach. LNAI 6270. FoLLI Publications on Logic, Language and Information. Springer 2010. 4.