@article{10_4153_CJM_1975_051_6,
     author = {Tyler, Robert},
     title = {On the {Lower} {Central} {Factors} of a {Free} {Associative} {Ring}},
     journal = {Canadian journal of mathematics},
     pages = {434--438},
     year = {1975},
     volume = {27},
     number = {2},
     doi = {10.4153/CJM-1975-051-6},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1975-051-6/}
}