With what accuracy can we measure masses if we have an (approximately known) mass standard

To measure masses with high accuracy, we need a mass standard. To make a standard work, we must have a procedure that will enable us to compare a mass of a physical body with the mass of a standard. This procedure has an error (as any other measurement procedure).To measure arbitrary masses (that are not necessarily equal to the mass of the standard), we must use an indirect measuring procedure. What potential accuracy can we attain in such a procedure? In this paper, we give an answer to this question.