1. ERROR BOUND FOR THE SOLUTION OF A POLYLOCAL PROBLEM WITH A COMBINED METHOD. Authors: DANIEL N. POP.2. A COLLOCATION METHOD USING CUBIC B-SPLINES FUNCTIONS FOR SOLVING SECOND ORDER LINEAR VALUE PROBLEMS WITH CONDITIONS INSIDE THE INTERVAL [0, 1]. Authors: DANIEL N. POP.3. APPROXIMATION METHODS FOR SECOND ORDER NONLINEAR POLYLOCAL PROBLEMS. Authors: DANIEL N. POP.