Apex Graph Grammars. - Joost Engelfriet; George Leih; Grzegorz Rozenberg (Graph-Grammars and Their Application to Computer Science, 1986)

Apex Graph Grammars and Attribute Grammars. - Joost Engelfriet; George Leih; Grzegorz Rozenberg (Acta Informatica, 1988)

Nonterminal Bounded NLC Graph Grammars. - Joost Engelfriet; George Leih (Theor. Comput. Sci., 1988)

Linear Graph Grammars: Power and Complexity - Joost Engelfriet; George Leih (Inf. Comput., 1989)

Net-Based Description Of Parallel Object-Based Systems, or POTs and POPs. - Joost Engelfriet; George Leih; Grzegorz Rozenberg (REX Workshop, 1990)

Complexity of boundary graph languages. - Joost Engelfriet; George Leih (RAIRO Theor. Informatics Appl., 1990)

Boundary Graph Grammars with Dynamic Edge Relabeling. - Joost Engelfriet; George Leih; Emo Welzl (J. Comput. Syst. Sci., 1990)

Nonterminal Separation in Graph Grammars. - Joost Engelfriet; George Leih; Grzegorz Rozenberg (Theor. Comput. Sci., 1991)

Context-Free Graph Languages of Bounded Degree are Generated by Apex Graph Grammars. - Joost Engelfriet; Linda Heyker; George Leih (Acta Informatica, 1994)