G. Grau, C. Cares, X. Franch, und F. Navarrete. International Conference on Software Engineering and Knowledge Engineering, San Francisco, CA, USA, (Juli 2006)
G. Gans, M. Jarke, G. Lakemeyer, und T. Vits. International Conference on Advanced Information Systems Engineering, 3248, Seite 328--343. Toronto, (Mai 2002)