Tsankova, Roumiana
[Author];
Andreev, Ognyan
[Author];
Daskalov, Hristian
[Author];
Petrov, Kamen
[Author];
Petrov, Velizar
[Author];
Georgieva, Mihaela
[Author];
Snezhana, Kondeva
[Author];
Tatarinceva, Anna
[Author];
Marinov, Orlin
[Author];
Malamov, Dobromir
[Author];
Angelova, Yordanka
[Author];
Gorcheva, Dilena
[Author];
Peneva, Gabriela
[Author];
Pavlova, Yoana
[Author];
Atanasova, Natalya
[Author]