S. Böttcher, L. Fernhomberg, and R. Hartel. WEBIST (Selected Papers), volume 101 of Lecture Notes in Business Information Processing, page 116-130. Springer, (2011)
S. Böttcher, R. Hartel, and C. Heinzemann. WEBIST (Selected Papers), volume 18 of Lecture Notes in Business Information Processing, page 65-79. Springer, (2008)