Authors
Valentin A. Skvortsov
Department of Mathematics, Moscow State University, Moscow
Francesco Tulone
francesco.tulone@math.unipa.it
Department of Mathematics and Computer Sciences, Palermo University, Palermo, Italy
francesco.tulone@math.unipa.it
© 2017 Valentin A. Skvortsov, Francesco Tulone, published by Slovak Academy of Sciences, Mathematical Institute
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.