The Guidelines include many examples of a range of pages for an entire article, book chapter, etc., but none for just that page (or perhaps two consecutive pages) that you quote from or otherwise refer to within an <analytic> or <monogr>. Right now, the only sensible element to use for this is <biblScope>, but if you use this, there's no recommended way to distinguish, say, a <biblScope> for the range of pages for a whole article in a journal issue and another <biblScope> for the two pages in a row from which a quotation is taken. This distinction is quite important for certain applications; for example, if you want to parse tagged citations to query against CrossRef's database to return a DOI for that item, you only want to send a page range for the whole article, not any particular pages that happen to be cited in your work.
That is, how do you cite a part of an <analytic> item, or a part of a <monogr> that doesn't have an <analytic>?
Our recommendation is:
A) to put this page range in a new element, <citedRange>(*), which would be a child of <biblStruct> (and sibling of <analytic>, <monogr>, and <series>). The cited pages/lines/sections aren't intrinsic to any particular level, so we would like them to live outside of all of the levels.
(* Alternative name suggestions welcome.)
If this is considered unpalatable or unnecessary, there are two possible compromises:
B) make <citedRange> not a sibling of monogr etc., but rather a child of <analytic> and of <monogr>. This has the disadvantage of being less obviously distinct in usage (and therefore in definition) from <biblScope>, but careful explanation and choice of examples may mitigate this.
C) use <biblScope> and an attribute to represent these semantics instead of new element. However this is potentially confusing, in that it encodes two rather different semantics in a single element. Also, a new attribute would be necessary, since @type is already used and would still be needed (what if you want to cite lines or columns or chapters rather than pages?). We feel biblScope doesn't sit very well as a sibling of monogr, either.
If (A) or (B) is chosen, we would also add this element as a child of <bibl>.
Examples would be updated throughout the Guidelines as appropriate.
There would be no change to the definition or examples of <extent>: it would still be used not for mentions of particular pages or volumes but for a statement like "4 vols.", "325 pages" or "97 minutes".