C. Geiger, G. Lehrenfeld, and W. Müller, “Visual Specification, Modeling, and Illustrations of Complex Systems,”10.1109/HICSS.1999.772621__presented at the Proceedings of the 32nd Annual Hawaii International Conference on Systems Sciences 1999, Maui, Hawaii, 1999, doi:10.1109/HICSS.1999.772621 .