@article{10_21136_CMJ_1989_102318,
     author = {Chajda, Ivan},
     title = {On {Gr\"atzer's} problem of binary 1-step congruence schemes},
     journal = {Czechoslovak Mathematical Journal},
     pages = {470--476},
     publisher = {mathdoc},
     volume = {39},
     number = {3},
     year = {1989},
     doi = {10.21136/CMJ.1989.102318},
     mrnumber = {1006312},
     zbl = {0687.08005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1989.102318/}
}