Returns a set of the laborcerthists associated with this labor, where laborcode=laborcode and qualificationid=:qualificationid and orgid=:orgid.  This will return 0 or more objects.
Vrne nabor laborcerthists, povezan s tem delom, kjer je laborcode=laborcode and qualificationid=:qualificationid and orgid=:orgid.  Vrne 0 ali več objektov.