Hung, Nguyen Viet
Zegadlo, Krzysztof
Ramaniuk, Aliaksandr
Konotop, Vladimir V.
Trippenbach, Marek
Article History
Received: 8 March 2017
Accepted: 15 May 2017
First Online: 22 June 2017
Competing Interests
: The authors declare that they have no competing interests.