T. Kaszuba, A. Hupa, and A. Wierzbicki. Local Proceedings of 13th East-European Conference, ADBIS 2009, page 374-384. JUMI Pubbbblishing House Ltd., (2009)
T. Kaszuba, P. Turek, A. Wierzbicki, and R. Nielek. Local Proceedings of 13th East-European Conference, ADBIS 2009, page 385-398. JUMI Pubbbblishing House Ltd., (2009)