6591c9e4_rel_values___Microformats_Wiki___specification_where_possible_
[Keyword] stylesheet [Effect on link] external resource [Effect on a, area] not allowed HTML4 Link types
a style sheet for the current document used with the invisible element which is not ideal for content relationships. Content relationships should be user visible and thus uses with are strongly preferred. Unfortunately the use of stylesheet in user visible content like appears to be strictly theoretical.
existing rel values · Microformats Wiki
Brief description (from the relevant specification where possible)