@article{DMGAA_2004_24_2_a1,
     author = {Chajda, Ivan},
     title = {A groupoid characterization of {Boolean} algebras},
     journal = {Discussiones Mathematicae. General Algebra and Applications},
     pages = {177--184},
     publisher = {mathdoc},
     volume = {24},
     number = {2},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGAA_2004_24_2_a1/}
}