@incollection{MEM_2021_50_a0,
     author = {Vassileva, Albena and Nikolov, Nikolai},
     title = {Fifty {Spring} {Conferences} of the {Union} of {Bulgarian} {Mathematicians} - the {Tradition} {Continues}},
     booktitle = {},
     series = {Mathematics and Education in Mathematics},
     pages = {9--22},
     year = {2021},
     volume = {50},
     language = {bg},
     url = {http://geodesic.mathdoc.fr/item/MEM_2021_50_a0/}
}