Sequence number of a document within the type of sequence named by the element to which this attribute is attached: on a <volume> element, the sequence within the volume; on an <issue> element, the sequence within the issue; on an <fpage> element, the sequence within a single page; and on an <elocation-id> element, the electronic sequence.
For journals (such as continuous-makeup journals) where more than one article can start on a single page, this attribute can record a sequence number or letter to differentiate one article from the other articles on the same page. For example, the first article to start on page 62 might be given a sequence of “ 62a ”; the sequence letter would be “ a ”, with a sequence letter “ b ” for a second article, etc.
|Data characters||Text, numbers, or special characters.|
|Restriction: This attribute may be specified if the element is used.|