When a standard is adopted, sometimes the adopting organization wraps their own metadata, front matter, and back matter around a standard, producing a combined, nested document. The <adoption-front> element contains the metadata, any beginning narrative material, and possible back matter that describes the adopting standard (<adoption>).
The following, in order:
<std-doc-meta> Standards Document Metadata, zero or one
<std-meta> NISO STS Standard Metadata, zero or one
Any combination of: