1. A NUMERICAL METHOD FOR APPROXIMATING THE SOLUTION OF A LOTKA-VOLTERRA SYSTEM WITH TWO DELAYS. Authors: DIANA OTROCOL.2. NUMERICAL SOLUTIONS OF LOTKA-VOLTERRA SYSTEM WITH DELAY BY SPLINE FUNCTIONS OF EVEN DEGREE. Authors: DIANA OTROCOL.3. HYBRID DIFFERENTIAL EQUATIONS WITH MAXIMA VIA PICARD OPERATORS THEORY. Authors: DIANA OTROCOL.4. SOME PROPERTIES OF SOLUTIONS TO A PLANAR SYSTEM OF NONLINEAR DIFFERENTIAL EQUATIONS. Authors: DIANA OTROCOL, VERONICA ILEA.