Kameas, A., and C. Karagiannidis,  "??????????? ????????? ???????? ??????????? ??? ???????????? ??????????",  ???????? ??? ?????????? ?????????????? ??? ?????????? - ????????? ??? ??????? ??????????? ??? ???????, ??????, ?????????? ????????? ??? ??????????? ??????, ???????? 15: ????????????, 2007.