@article{10_21136_CMJ_1977_101492,
     author = {Chao, Chong-Yun and Winograd, Shmuel},
     title = {A generalization of a theorem of {Boolean} relation matrices},
     journal = {Czechoslovak Mathematical Journal},
     pages = {552--555},
     publisher = {mathdoc},
     volume = {27},
     number = {4},
     year = {1977},
     doi = {10.21136/CMJ.1977.101492},
     mrnumber = {0463207},
     zbl = {0386.15014},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1977.101492/}
}