For a more up-to-date list, see the i-star group library on CiteULike --> all articles with tag __metamodel.
You can narrow the search by using a search phrase such as -->
"+tag:(__metamodel AND __requirements-engineering AND __security)".
- Paolo Giorgini. John Mylopoulos. Anna Perini. Angelo Susi. The Tropos Metamodel and its Use. Informatica journal. 2005.
- Claudia P. Ayala, Carlos Cares, Juan P. Carvallo, Gemma Grau, Mariela Haya, Guadalupe Salazar, Xavier Franch, Enric Mayol, Carmen Quer. A Comparative Analysis of i*-Based Goal-Oriented Modelling Languages, International Workshop on Agent-Oriented Software Development Methodologies (AOSDM '05), at the SEKE Conference. July 2005. Taipei, Taiwán; China.
- Roy, J.-F. Kealey, and Amyot, D. Towards Integrated Tool Support for the User Requirements Notation. In: R. Gotzhein, R. Reed (Eds.) SAM 2006: Language Profiles - Fifth Workshop on System Analysis and Modelling, Kaiserslautern, Germany, May. LNCS 4320, 198-215, Springer. (2006)
- see also the i* tools metamodels page.