On multiplicative systems
Compositio Mathematica, Tome 8 (1951) , pp. 76-80.
@article{CM_1951__8__76_0,
     author = {Levitzki, Jakob},
     title = {On multiplicative systems},
     journal = {Compositio Mathematica},
     pages = {76--80},
     publisher = {Kraus Reprint},
     volume = {8},
     year = {1951},
     zbl = {0033.34801},
     mrnumber = {33799},
     language = {en},
     url = {archive.numdam.org/item/CM_1951__8__76_0/}
}
Levitzki, Jakob. On multiplicative systems. Compositio Mathematica, Tome 8 (1951) , pp. 76-80. http://archive.numdam.org/item/CM_1951__8__76_0/