Adams, M. E.
Sankappanavar, H. P.
de Carvalho, Júlia Vaz
Funding for this research was provided by:
Fundação para a Ciência e a Tecnologia (The projects UID/MAT/00297/2013 and UID/MAT/00297/2019 (Centro de Matemática e Aplicações).)
Article History
Received: 24 July 2019
Accepted: 28 November 2019
First Online: 10 January 2020