@article{CMUC_1987__28_4_a16,
     author = {Duda, Jarom{\'\i}r},
     title = {Identities for direct decomposability of congruences can be written in two variables},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     publisher = {mathdoc},
     volume = {28},
     number = {4},
     year = {1987},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1987__28_4_a16/}
}