@article{10_4064_cm_27_2_193_195,
     author = {J. P{\l}onka},
     title = {On the join of equational classes of idempotent algebras and algebras with constants},
     journal = {Colloquium Mathematicum},
     pages = {193--195},
     publisher = {mathdoc},
     volume = {27},
     number = {2},
     year = {1973},
     doi = {10.4064/cm-27-2-193-195},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-27-2-193-195/}
}