@article{RSMUP_2016__136__19_0,
     author = {Tomaszewski, Witold},
     title = {On laws of the form $ab\equiv ba$ equivalent to the abelian law},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {19--34},
     publisher = {European Mathematical Society Publishing House},
     address = {Zuerich, Switzerland},
     volume = {136},
     year = {2016},
     doi = {10.4171/RSMUP/136-3},
     url = {http://archive.numdam.org/articles/10.4171/RSMUP/136-3/}
}