Todorova, Totka
Shestakova, Pavletta
Petrova, Tanya
Popova, Margarita
Lazarova, Hristina
Kalvachev, Yuri http://orcid.org/0000-0002-4084-8458
Funding for this research was provided by:
Bulgarian National Science Fund (KP-06-5)
Bulgarian Ministry of Education and Science (Contract D01-284/17.12.2019)
European Regional Development Fund (BG05M2OP001-1.001-0008)
Article History
Received: 4 May 2020
Accepted: 28 June 2020
First Online: 6 July 2020