TY - JOUR AU - T.E. Hall TI - On bands, free bands and identities. JO - Semigroup forum PY - 1971 SP - 83 EP - 84 VL - 2 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/SF_1971__2_133815/ ID - SF_1971__2_133815 ER -