He, Xiao; Ma, Zhiyi; Shao, Weizhong; Li, Ge (July 2007). "A metamodel for the notation of graphical modeling languages". 31st Annual International Computer Software and Applications Conference - Vol. 1- (COMPSAC 2007). Vol. 1. pp. 219–224. CiteSeerX10.1.1.526.5321. doi:10.1109/COMPSAC.2007.27. ISBN978-0-7695-2870-0.
Breteler, Jeroen; van Gessel, Thom; Biagioni, Giulia; van Doesburg, Robert (2023-09-11), Acosta, Maribel; Peroni, Silvio; Vahdati, Sahar; Gentile, Anna-Lisa (eds.), "The FLINT Ontology: An Actor-Based Model of Legal Relations", Studies on the Semantic Web, IOS Press, doi:10.3233/ssw230016, ISBN978-1-64368-424-6
He, Xiao; Ma, Zhiyi; Shao, Weizhong; Li, Ge (July 2007). "A metamodel for the notation of graphical modeling languages". 31st Annual International Computer Software and Applications Conference - Vol. 1- (COMPSAC 2007). Vol. 1. pp. 219–224. CiteSeerX10.1.1.526.5321. doi:10.1109/COMPSAC.2007.27. ISBN978-0-7695-2870-0.