Kirilova-Doneva, Miglena
Pashkouleva, Dessislava
Stoytchev, Stoyan
Article History
Received: 24 September 2019
Accepted: 26 March 2020
First Online: 16 May 2020
Compliance with ethical standards
:
: All procedures performed in studies were in accordance with the ethical standards of the institutional Ethics Committee at Bulgarian Academy of Sciences (reference number N36/24.02.2016) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.