Simov, Kiril
Koprinkova-Hristova, Petia http://orcid.org/0000-0002-0447-9667
Popov, Alexander
Osenova, Petya
Funding for this research was provided by:
Ministry of Education, Youth and Science
Article History
Received: 11 February 2020
Accepted: 23 July 2020
First Online: 7 September 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.