Silviya Krumova, Nelly Sivkova, Vassil Marinov, Desislava 
Koleva-Georgieva, Desislava Voynikova

_{Folia Medica 62(2): 338-344 Research article
DOI: 10.3897/folmed.62.e46678}

https://foliamedica.bg/article/46678/