@article{SF_1980__21_134452,
     author = {A. Mukherjea and R. Chaudhuri},
     title = {Idempotent {Boolean} matrices.},
     journal = {Semigroup forum},
     pages = {273--282},
     publisher = {mathdoc},
     volume = {21},
     year = {1980},
     zbl = {0449.16010},
     url = {http://geodesic.mathdoc.fr/item/SF_1980__21_134452/}
}