homepages/220/7739,
University of Barcelona, Department of Mathematics and Computer Science, Spain, Rubén Ballester and Rubén Ballester Bautista, Home Page, https://twitter.com/rballeba
homepages/220/0767,
Universiti Sains Malaysia, Minden, Malaysia, Oludare Isaac Abiodun and Isaac Oludare Abiodun, Home Page, https://orcid.org/0000-0003-0138-6446