duong@imi.kyushu-u.ac.jp
p-mishra@math.kyushu-u.ac.jp
yasuda@imi.kyushu-u.ac.jp
© 2017 Dung Hoang Duong, Pradeep Kumar Mishra, Masaya Yasuda, published by Slovak Academy of Sciences, Mathematical InstituteThis work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.