https://plusbg.eu/author/a-dimitrova/https://plusbg.eu/author/a-yanev/https://plusbg.eu/author/delga/https://plusbg.eu/author/gbx/https://plusbg.eu/author/nvarbanova/https://plusbg.eu/author/r-barakovska/https://plusbg.eu/author/t-pulev/