HTML does contain a number of link types. A few of them—author, bookmark, help, license, pingback, search, stylesheet, tag—even encode relationships, albeit weak ones in some cases. (Tag could be anything from a country to a topic to a sector to an audience.)
But most HTML link types are instructions for machines (canonical, no-follow, prefetch) or for navigation (up, previous, last).
What they don't do (but should!) is encode editorial (read: rhetorical) intent. Those could be as simple as a link type called reference or note. Or they could also be much more complex, with types like methodology or findings.