1. On multiple context-free grammars;Seki;Theor. Comput. Sci.,1991
2. Tree adjoining grammars: how much context-sensitivity is required to provide reasonable structural descriptions?;Joshi,1985
3. MIX is not a tree-adjoining language;Kanazawa,2012
4. The pumping lemma for well-nested multiple context-free languages;Kanazawa,2009