This attribute is used with two different definitions.
The most common is the name of the thesaurus, ontology, or organization that established
a particular group of keywords, for example, MESH
, ISO-463
, IEEE
, author-generated
, ICD9-codes
, etc.
The second usage describes the type of keyword
for some of the more unusual keyword groups (for
example, hierarchical
for keywords that
are grouped into a hierarchy,
abbreviations
for
keywords that contain an abbreviation and its expansion,
or code
for
keywords that contain a code
and its text but where the source of the codes is unknown).
| Value | Meaning |
|---|---|
| Text, numbers, or special characters | The source of keywords. This may be an organization (such as IEEE) or the name of a thesaurus, subject index, or ontology (such as MESH). |