Beschkov, V. https://orcid.org/0000-0003-3635-6810
Alexieva, Z.
Parvanova-Mancheva, Ts.
Vasileva, E.
Gerginova, M.
Peneva, N.
Stoyanova, K.
Funding for this research was provided by:
Fund for Scientific Research, Bulgaria (DN 17/4, 2017)
Article History
Received: 30 May 2019
Revised: 7 November 2019
Accepted: 12 November 2019
First Online: 16 November 2019
Compliance with ethical standards
:
: The authors of this paper declare there were no conflict of interest during its work and preparation.