Let M be a right R-module. Define Z (N) ( 8 M (N )) to be the set of elements n e N for any R- module N in a[M] such that nR is an M-small (respectively 8-M-small) modüle. In this note it is proved that M is a GCO-module if and only if every M-small modüle in o[M] is M-projective if and only if every * 8-M-small modüle in o[M] is M-projective. Also, if M/8 M (M) is semisimple then M is a GCO-module if and only if M is an Sl-module.