TY  - JOUR
AU  - R. M. Capocelli
TI  - On some subsemigroups of a free semigroup.
JO  - Semigroup forum
PY  - 1977
SP  - 125
EP  - 136
VL  - 15
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SF_1977__15_134243/
ID  - SF_1977__15_134243
ER  -