D. Cernea, P. Olech, A. Ebert, and A. Kerren. VLUDS, volume 27 of OASIcs, page 113-122. Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, Germany, (2011)
D. Cernea, P. Olech, A. Ebert, and A. Kerren. HCI (23), volume 174 of Communications in Computer and Information Science, page 279-283. Springer, (2011)