Angelov, George Vasilev http://orcid.org/0000-0001-7602-3960
Nikolakov, Dimitar Petrov http://orcid.org/0000-0001-5473-0883
Ruskova, Ivelina Nikolaeva http://orcid.org/0000-0003-2010-749X
Gieva, Elitsa Emilova http://orcid.org/0000-0002-2705-1954
Spasova, Maria Liubomirova http://orcid.org/0000-0001-7375-5277
Chapter History
First Online: 19 January 2019