Authors
Pierre Popoli
pierre.popoli@univ-lorraine.fr
Institut Élie Cartan de Lorraine, Université de Lorraine, France
pierre.popoli@univ-lorraine.fr
© 2020 Pierre Popoli, published by Slovak Academy of Sciences, Mathematical Institute
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.