Affiliation: | (1) Milovanovi and Stojanovi, Faculty of Electronic Engineering, Beogradska 14, P. O. Box 73, 18000 Ni, Yugoslavia;(2) Catedra de Matematici, Institutul Politehnic, R-3400 Cluj-Napoca, Romania;(3) Gradjevinski fakultet, Bulevar Revolucije 73, 11000 Beograd, Yugoslavia |