A non-commutative free algebra of rank 0
Rendiconti del Seminario Matematico della Università di Padova, Tome 77 (1987) , pp. 207-211.
@article{RSMUP_1987__77__207_0,
     author = {Wiegold, James},
     title = {A non-commutative free algebra of rank $0$},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {207--211},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {77},
     year = {1987},
     zbl = {0625.08006},
     mrnumber = {904622},
     language = {en},
     url = {http://www.numdam.org/item/RSMUP_1987__77__207_0/}
}
Wiegold, James. A non-commutative free algebra of rank $0$. Rendiconti del Seminario Matematico della Università di Padova, Tome 77 (1987) , pp. 207-211. http://www.numdam.org/item/RSMUP_1987__77__207_0/

[1] G.D. Birkhoff, On the structure of abstract algebras, Proc. Cambridge Philos Soc., 31 (1935), pp. 433-454. | JFM 61.1026.07

[2] M.I. Kargapolov - Yu I. Merzlyakov - V.N. Remeslennikov, Completion of groups, Dokl. Akad. Nauk SSSR, 134 (1960), pp. 518-520. | MR 125160 | Zbl 0097.01402

[3] J.D. Ledlie, Representations of free metabelian Dπ-groups, Trans. Amer. Math. Soc., 153 (1971), pp. 307-446. | Zbl 0216.08303

[4] B.H. Neumann - E.C. Wiegold, A semigroup representation of varieties of algebras, Coll. Math., 14 (1966), pp. 111-114. | MR 191984 | Zbl 0192.09602