For documents which are supplements to a standard, gives the document number of the supplement.
The content of this element is typically a sequence of digits.
For documents which are not supplements, the element may be omitted, or it may be present but empty.
ISO Note: For ISO standards documents that are not supplements, the ISO STS Tag Set required this element, so the element needed to be present, but empty. If the element is empty for a document which is a supplement, the <suppl-number> element will be treated as having the number “1”.
Text, numbers, or special characters, zero or more
... <std-ident> <originator>CEN</originator> <doc-type>EN</doc-type> <doc-number>3951</doc-number> <part-number>2</part-number> <edition>1</edition> <version>1</version> <suppl-type>1</suppl-type> <suppl-number>1</suppl-number> <suppl-version>2</suppl-version> </std-ident> ...