Question about characters in DOI suffixes

I found issues with DOIs yesterday when running this API request:

https://0-api-crossref-org.pugwash.lib.warwick.ac.uk/journals/1097-0266/works?select=DOI,title,published,is-referenced-by-count&sort=is-referenced-by-count&order=desc&rows=50

This was a polite-pool request.

A number of DOIs have been formatted as follows, for example:

10.1002/(sici)1097-0266(199708)18:7<509::aid-smj882>3.0.co;2-z
10.1002/1097-0266(200010/11)21:10/11<1105::aid-smj133>3.0.co;2-e
10.1002/(sici)1097-0266(199804)19:4<293::aid-smj982>3.0.co;2-m

Is this a known bug?

Cheers,

Dave

1 Like

Hi Dave,

Thanks for your question.

Those are actually legitimate DOIs.

For the first few years of Crossref’s existence, the characters that were allowed in DOI suffixes were much more expansive. Over time, we found that certain kinds of characters (for example, angle brackets, colons, question marks, hash/pound signs) were causing problems for certain linking and query systems.

So, eventually suffix characters were limited to just A-Z, a-z, 0-9 and the following special characters: - . _ ; ( ) /

But those older DOIs still exist and are in use.

Please let me know if you have any questions.

Best,
Shayn

2 Likes

Hi Shayn,

Thank you for your response.
My apologies; this is the very first time I see these type of DOIs.

I see them at the publisher’s site now as well. My mistake.

Kind Regards,

Dave

1 Like