Georgieva, Katya http://orcid.org/0000-0002-5509-3801
Mihailova, Gergana http://orcid.org/0000-0001-6006-6720
Gigova, Liliana
Dagnon, Soleya http://orcid.org/0000-0001-6570-4947
Simova-Stoilova, Lyudmila http://orcid.org/0000-0003-1590-294X
Velitchkova, Maya http://orcid.org/0000-0002-7926-5292
Article History
Received: 19 November 2020
Revised: 19 February 2021
Accepted: 20 April 2021
First Online: 7 May 2021