TY  - JOUR
AU  - G. Markowsky
TI  - Ordering D-classes and computing Schein rank is hard.
JO  - Semigroup forum
PY  - 1992
SP  - 373
EP  - 375
VL  - 44
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SF_1992__44_1_135161/
ID  - SF_1992__44_1_135161
ER  -