Georgiev, Tsvetoslav
Stoilov, Rumen
Article History
Received: 16 October 2018
Accepted: 2 November 2018
First Online: 9 November 2018
Compliance with ethical standards
:
: This article does not contain any studies with human participants or animals performed by any of the authors.
: Tsvetoslav Georgiev declares that he has no conflict of interest. Rumen Stoilov declares that he has no conflict of interest.