Presence of the attribute indicates that the content of a citation has been replaced or augmented with content obtained from one or more linking services, such as PubMed, CrossRef, or PsycINFO. The attribute value indicates which service or services provided the revised content.
| Value | Meaning |
|---|---|
| Any combination of | |
| PI | revised content was obtained from PsycINFO |
| CR | revised content was obtained from CrossRef |
| PM | revised content was obtained from PubMed |
| Restriction: This attribute may be specified if the element is used. | |