@incollection{MEM_2010_39_1_a17,
     author = {Dimitrov, Vladimir},
     title = {Formal {Specification} of {Relational} {Model} of {Data} in {Z-Notation}},
     booktitle = {},
     series = {Mathematics and Education in Mathematics},
     pages = {178--183},
     year = {2010},
     volume = {39},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MEM_2010_39_1_a17/}
}