Volkov, M. K.
Pivovarov, A. A.
Article History
Received: 5 December 2018
Revised: 5 December 2018
Accepted: 14 December 2018
First Online: 6 May 2019
Change Date: 27 August 2019
Change Type: Erratum
Change Details: In Eqs. (12), in line 16 should be replaced by