Vatiwutipong, P.
Phewchean, N. http://orcid.org/0000-0002-3796-3527
Funding for this research was provided by:
Centre of Excellence in Mathematics, Thailand (1)
Article History
Received: 9 April 2019
Accepted: 2 July 2019
First Online: 17 July 2019
Competing interests
: The authors declare that they have no competing interests.
: All authors have seen and approve the submission of this manuscript.