Hello and thank you for taking the time to post this article.
As for Prof. Dr. Dimitrakiev, check the following sources:
Profile at the Naval Academy:
http://www.naval-acad.bg/en/archives/resume/dimitar-jordanov-dimitrakiev
Profile at Varna University of Management:
http://www.vumk.eu/en/lecturer/15-доц-д-р-инж-димитър-димитракиев
Scientific works at ResearchedID:
http://www.researcherid.com/rid/E-3595-2012
Scientific works at elibrary.eu:
https://elibrary.ru/author_items.asp?authorid=633405
Scientific works as Scopus:
https://www.scopus.com/authid/detail.uri?origin=AuthorProfile&authorId=35608183100&zone=