FACTA UNIVERSITATIS SERIES MATHEMATICS AND INFORMATICS, Vol. 13, 1998 Contents Z. Marković Intuitionistic and Classical Satisfability in Kripke Models Ž. Mijajlović and Z. Marković Some Recurrence Formulas to the Differential Operator 0D V.Yu. Protasov Generalisation of the Joint Spectral Radius: The Geometrical Approach G.B. Đorđević Polynomials Related to Gegenbauer Polynomials S. Pilipović and M. Stojanović Generalized Goursat Problem and the Quasiasymptotics of a Solution A. Tali On Convex Families of Summability Methods Lj.M. Kocić and B. Della Vecchia Degeneracy of Positive Linear Operators Y.L. Nosenko Approximation of the Function by Fourier Series E. Bairamov and A.O. Celebi Spectral Analysis of Nonselfadjoint Schrodinger Operators With Spectral Parameter in Boundary Conditions D.M. Milošević and Lj.M. Kocić Fractal Surfaces Leveling S. Janković and M. Jovanović A General Algorithm for Solving Stochastic Hereditary Integrodifferential Equations M.R. Capobianco and N. Mastronardi A Numerical Method for a Volterra-type Integral Equations With Logarithmic Kernel K. Stevanović Hedrih Derivatives of the Mass Moment Vectors at the Dimensional Coordinate System N V. Stojanović, S. Radovanović and J. Bogdanović Least Squres Approximation of Multi-port Network Parameters by Rational Functions