Vladimir Simov Jotsov Mincho Bankov Hadjiski Vassil Stoyanov Sgurev Methodologies and applications in contemporary intelligent systems. 855-857 2005 36 Int. J. Systems Science 14 http://dx.doi.org/10.1080/00207720500382431 db/journals/ijsysc/ijsysc36.html#JotsovHS05