COMA and related ideas have been documented in the following articles (downloadable):

1. Rittgen, Peter: Success Factors of e-Collaboration in Business Process Modeling, in Pernici, Barbara (ed.): Advanced Information Systems Engineering, 22nd International Conference, CAiSE 2010, Hammamet, Tunisia, June 2010, Proceedings, LNCS 6051, Berlin, Germany: Springer, 2010, pp. 24-37
2. Rittgen, Peter: Quality and Perceived Usefulness of Process Models, Proceedings of the 25th Annual ACM Symposium on Applied Computing, March 22 - 26, 2010, Sierre, Switzerland, 2010, pp. 65-72
3. Rittgen, Peter: Collaborative Business Process Modeling – Tool Support for Solving Typical Problems, Proceedings of the Conf-IRM 2010 "Collaboration and Community in a Global World", May 16 - 18, 2010, Montego Bay, Jamaica, 2010
4. Rittgen, Peter: Self-organization of interorganizational process design, Electronic Markets, 19(4), 2009, pp. 189-199
5. Rittgen, Peter: Collaborative Modeling, Business Process Magazine, 7, 2009, pp. 32-35
6. Rittgen, Peter: Collaborative Modeling – A Design Science Approach, Proceedings of the 42nd Hawaii International Conference on System Sciences (HICSS-42), Waikoloa, Big Island, Hawaii, USA, January 5-8, 2009, CD-ROM, Los Alamitos, CA: IEEE Computer Society, 2009, 10 p. (nominated for best paper award)
7. Rittgen, Peter: COMA: A Tool for Collaborative Modeling, in Bellahsene, Zohra; Woo, Carson; Hunt, Ela; Franch, Xavier; Coletta, Remi (eds.): Proceedings of the Forum at the CAiSE'08 Conference, Montpellier, France, June 18-20, 2008. CEUR Workshop Proceedings 344, CEUR-WS.org, 2008, pp. 61-64
8. Rittgen, Peter: Negotiating Models, in Krogstie, John; Opdahl, Andreas; Sindre, Guttorm (eds.): Advanced Information Systems Engineering, 19th International Conference, CAiSE 2007, Trondheim, Norway, June 2007, Proceedings, LNCS 4495, Berlin, Germany: Springer, 2007, pp. 561-573