@incollection{MEM_2021_50_a2,
     author = {Popivanov, Peter},
     title = {90th {Anniversary} of {Prof.} {Racho} {Denchev}},
     booktitle = {},
     series = {Mathematics and Education in Mathematics},
     pages = {39--41},
     year = {2021},
     volume = {50},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MEM_2021_50_a2/}
}