Nguyen, Hop Dang
Trung, Ngo Viet
Article History
Received: 23 September 2018
Accepted: 30 May 2019
First Online: 13 July 2019
Change Date: 11 October 2019
Change Type: Correction
Change Details: The original proof of TheoremĀ 3.3 incorrect. The correction concerns only this proof and does not affect any result of the paper.