Authors
Dorin Andrica
Department of Mathematics, “Babeş-Bolyai” University, Cluj Napoca, Mihail Kogalniceanu Street 1,, Cluj-Napoca, Romania
Vlad Crişan
vlad.crisan@mathematik.uni-goettingen.de
Department of Mathematics, University of Göttingen, Bunsenstra 19;e 3-5,, Göttingen, Germany