Ignatova, Desislava
Kamusheva, Maria
Petrova, Guenka
Onchev, Georgi
Article History
Received: 15 September 2018
Accepted: 22 March 2019
First Online: 30 March 2019
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: The study was conducted in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. The study protocol was approved by the ethics committee of the Medical University of Sofia. All participants gave written informed consent prior to their inclusion in the study and their anonymity was guaranteed.