@article{1195519343,
author = {Higgins, John C. and Tamura, Takayuki},
title = {Finitely generated $\mathfrak{N}$-semigroup and quotient group},
journal = {Proc. Japan Acad.},
volume = {49},
number = {9},
year = {1973},
pages = { 323-327},
language = {en},
url = {http://dml.mathdoc.fr/item/1195519343}
}
Higgins, John C.; Tamura, Takayuki. Finitely generated $\mathfrak{N}$-semigroup and quotient group. Proc. Japan Acad., Tome 49 (1973) no. 9, pp. 323-327. http://gdmltest.u-ga.fr/item/1195519343/