The following conventions are used in the assignment of coded values in the [[ Hold/Record label|Record Label ]] and coded

:'''<nowiki># </nowiki>''' - Information not available.:'''u ''' - Unknown. Used when codes are being assigned, but the appropriate specific value cannot be determined.:'''x ''' - Not applicable. Used when a characteristic is not appropriate for the type of entity being described.:'''y ''' - Not present. Used when the characteristic being coded is not present for the entity being described.:'''z ''' - Other. Used when codes are being assigned and the characteristics of the entity are known, but none of the defined codes is appropriate.:'''| ''' - Fill character. Used when no attempt is being made to assign the codes.