A @[email protected] taken, prepared and stored in an agreed upon manner for the purpose of settling a dispute. The agreement usually extends beyond the sample to the basis for reaching a decision (e.g. quantity of material from which taken, use of a third party and criteria serving as the basis for acceptance, rejection or economic adjustment). The term 'reference sample' has been used in this context but this term more properly should be used in conjunction with a '@[email protected]' or 'reference standard' which has a true or assigned value for a @[email protected] or property. One of the characteristics of a @[email protected] or reference standard is that it must have a negligible @[email protected] between test portions.