zbigwrob@op.pl
gaworj@twarda.pan.pl
taniak@izan.kiev.ua
© 2016 K. Slivinska, V. Kharchenko, Z. Wróblewski, J. Gawor, T. Kuzmina, published by Slovak Academy of Sciences, Mathematical InstituteThis work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.