@article{DMGAA_2015_35_1_a1,
     author = {Dymek, Grzegorz},
     title = {On a period of elements of {pseudo-BCI-algebras}},
     journal = {Discussiones Mathematicae. General Algebra and Applications},
     pages = {21--31},
     publisher = {mathdoc},
     volume = {35},
     number = {1},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGAA_2015_35_1_a1/}
}