V. Karkaletsis, P. Fragkou, G. Petasis, and E. Iosif. volume 6050 of Lecture Notes in Computer Science, page 89--109. Springer Berlin / Heidelberg, (2011)10.1007/978-3-642-20795-2_4.
D. Spiliotopoulos, G. Petasis, and G. Kouroupetroglou. volume 5246 of Lecture Notes in Computer Science, page 517--524. Springer Berlin / Heidelberg, Brno, Czech Republic, (September 2008)