Added a reference to the EDUPUB Structural Semantics profile

Although it has been done for the educational market, there may lots of similarities with the scholarly documents, worth considering it, too:

http://www.idpf.org/epub/profiles/edu/structure/ <http://www.idpf.org/epub/profiles/edu/structure/>

Ivan

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Ivan Herman, W3C
Digital Publishing Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
ORCID ID: http://orcid.org/0000-0003-0782-2704