When an edition, version, or similar statement contains ordinals (such as “3rd”) or words such as “3rd print edition”, this attribute can preserve the edition/version number as a simple, machine-processable number, such as “3”.
OPTIONAL on many elements; click for list and usage
|The numeral or alphabetic character(s) that indicates the version number, edition number, etc.||The unadorned number that indicates the simple, machine-processable value of the element’s content. Typically this is a number such as “4” or an alphabetic character such as “A”, while the element content may contain ordinals or other text.|
|Restriction||@designator is an optional attribute; there is no default.|
... <mixed-citation> <collab>National Committee for Clinical Laboratory Standards</collab>. <source>Performance standards for antimicrobial disk susceptibility tests</source>. <comment>Approved standard</comment>. <edition designator="7">7<sup>th</sup> ed.</edition> p. <fpage>M2</fpage>–<lpage>A7</lpage>. ... </mixed-citation> ...