Encoding key-value pairs in an <abstract>

What is the best way to encode abstracts that are essentially just key-value pairs?

Consider formulaic abstracts such as these:

This document is a [writ|deed|charter]. The court of authority is [papal|secular]. The witness to the document is [insert someone’s name].

The inventor was [insert name]. The researched drug was [insert chemical name]. The test facility was [hospital|military facility|university].

Only the parameters are important. I don’t really need the introductory words.

I’m looking for something like this:
<abstract>
	<list>
		<item type="type">charter</item>
		<item type="court">secular</item>
		<item type="witness">someone’s name</item>
	</list>
</abstract>

But @type isn’t an attribute of <item> and <item> seems semantically wrong. <keywords> doesn’t work for key-value pairs. <classCode> doesn’t seem right. <catRef> seems overly complicated.

What is the best approach, sticking to the stock schema?

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