@incollection{MEM_2023_52_a14,
     author = {Georgieva, Desislava},
     title = {Methodological developments for the introduction of basic concepts from combinatorics},
     booktitle = {},
     series = {Mathematics and Education in Mathematics},
     pages = {172--179},
     year = {2023},
     volume = {52},
     language = {bg},
     url = {http://geodesic.mathdoc.fr/item/MEM_2023_52_a14/}
}