1. DIRECT MICROWAVE ABSORPTION INVESTIGATION OF THE YBa2Cu3O7-:Li SUPERCONDUCTOR SYSTEM. Authors: M. VELTER-STEFANESCU, O.G. DULIU, V. SANDU, I. URSU.2. SOME CONSIDERATIONS CONCERNING THE RELAXATION OF THE RADIATION FREE RADICALS IN POLYMERS. Authors: M. VELTER-STEFANESCU, O.G. DULIU, N. PREDA, I. URSU.3. EPR LINE SHAPE AS A CRITERION IN PROVENANCE STUDIES OF LIMESTONES AND MARBLES. Authors: O.G. DULIU, M. VELTER-STEFANESCU, I. URSU.4. STUDY BY MAGNETICALLY MODULATED MICROWAVE ABSORPTION OF BI1.7PB0.4SR1.5CA2.5CU3.6OX/ (LIF)Y SUPERCONDUCTING SYSTEM. Authors: M. VELTER-STEFANESCU, O.G. DULIU, V. MIHALACHE, I. URSU.