FACTA UNIVERSITATIS SERIES MATHEMATICS AND INFORMATICS, Vol. 23 (2008) Contents B.G Pachpatte On Certain Volterra Integral and Integro-Di erential Equations M. Tilca A K-Functional Characterization of the Spline Approximation C. Radu Variation Detracting Property of the Bezier Type Operators G.V. Milovanović, A.S. Cvetković and M.P. Stanić Christoffel-Darboux Formula for Orthogonal Trigonometric Polynomials of Semi-Integer Degree S.S. Dragomir and M.S. Moslehian Some Inequalities for ( ; )-Normal Operators in Hilbert Spaces V. Stojanović and B. Popović Discrete Autoregressive Stopping Time Model M. Acharya, B. P. Acharya and M. M. Nayak Approximate Evaluation of Integrals of Analytic Functions Author Index Volumes 1 - 23 (1986 - 2008)