@article{10_21136_CMJ_1983_101874,
     author = {Magill, Kenneth D., Jr. and Misra, P. R. and Tewari, U. B.},
     title = {Symons' $d$-congruence on sandwich semigroups},
     journal = {Czechoslovak Mathematical Journal},
     pages = {221--236},
     publisher = {mathdoc},
     volume = {33},
     number = {2},
     year = {1983},
     doi = {10.21136/CMJ.1983.101874},
     mrnumber = {699023},
     zbl = {0525.20052},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1983.101874/}
}