@article{ITA_2012__46_2_261_0,
     author = {Cantone, Domenico and Formisano, Andrea and Asmundo, Marianna Nicolosi and Omodeo, Eugenio Giovanni},
     title = {A graphical representation of relational formulae with complementation},
     journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications},
     pages = {261--289},
     publisher = {EDP-Sciences},
     volume = {46},
     number = {2},
     year = {2012},
     doi = {10.1051/ita/2012003},
     mrnumber = {2931249},
     zbl = {1254.03020},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/ita/2012003/}
}