H. Schärfe, U. Petersen, and P. Øhrstrøm. Proceedings of the 10th International Conference on Conceptual Structures (ICCS 2002), volume 2393 of Lecture Notes in Computer Science, page 285-298. Springer, (2002)
F. Weitl, C. Süß, R. Kammerl, and B. Freitag. Proceedings of e-Learn 2002 world conference on E-Learning in Corporate, Government, Healthcare, and Higher Education, page 1018-1025. (2002)
O. Rostanin, and R. Schirru. Proceedings of the Joint International Workshop on Professional Learning, Competence Development and Knowledge Management - LOKMOL and L3NCD held in conjunction with the 1st European Conference on Technology Enhanced Learning, page 53-58. (October 2006)
J. Tane, C. Schmitz, G. Stumme, S. Staab, and R. Studer. Mobiles Lernen und Forschen - Beiträge der Fachtagung an der Universität, page 93-104. Kassel University Press, (November 2003)