In reply to a post on twitter.com
@MsPhelps @jeroenson @jeroenbosman @mfenner @CrossrefOrg Interesting. An oversight on our part which we should fix. Crossref Metadata Search (which uses the API), does deal with them, though not elegantly: https://search.crossref.org/?q=http%3A%2F%2Fdoi.org%2Fhvx