Authors
Grigore Călugăreanu
Department of Mathematics, Babeş - Bolyai University, str. Kogălniceanu 1,, Constanta, Romania
© 2018 Grigore Călugăreanu, published by Ovidius University of Constanta
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.