@article{10_4064_fm_64_2_241_247,
     author = {Jerzy P{\l}onka},
     title = {On equational classes of abstract algebras defined by regular equations},
     journal = {Fundamenta Mathematicae},
     pages = {241--247},
     publisher = {mathdoc},
     volume = {64},
     number = {2},
     year = {1969},
     doi = {10.4064/fm-64-2-241-247},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-64-2-241-247/}
}