Extent value

The numeric value of the extent specified in <ExtentType>. Optional, and non-repeating. However, either <ExtentValue> or <ExtentValueRoman>, or both, must be present in each occurrence of the <Extent> composite; and it is very strongly recommended that <ExtentValue> should always be included, even when the original product uses Roman numerals.

Format	Positive real number, with explicit decimal point when required, as appropriate for the units specified in <ExtentUnit>. Suggested maximum length 8 characters
ReferenceName	<ExtentValue>
ShortTag	<b219>
Cardinality	0…1
Example	2.5