À propos de cet article
Publié en ligne: 13 nov. 2012
Pages: 71 - 77
DOI: https://doi.org/10.2478/v10127-010-0021-x
Mots clés
This content is open access.
Jaroslav Šupina
Institute of Mathematics University of P. J. Šafárik Jesenná 5 SK–040-01 Koˇsice SLOVAKIA