TY  - JOUR
AU  - A.N. Petrov
TI  - The ascending varietal chain of a variety of semigroups.
JO  - Semigroup forum
PY  - 1986
SP  - 157
EP  - 162
VL  - 35
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SF_1986__35_134865/
ID  - SF_1986__35_134865
ER  -