2020 wasn’t all bad. In April of last year, we released our first public data file. Though Crossref metadata is always openly available––and our board recently cemented this by voting to adopt the Principles of Open Scholarly Infrastructure (POSI)––we’ve decided to release an updated file. This will provide a more efficient way to get such a large volume of records. The file (JSON records, 102.6GB) is now available, with thanks once again to Academic Torrents.
Our colleague and friend, Kirsty Meddings, passed away peacefully on 10th December at home with her family, after a sudden and aggressive cancer. She was a huge part of Crossref, our culture, and our lives for the last twelve years.
Kirsty Meddings is a name that almost everyone in scholarly publishing knows; she was part of a generation of Oxford women in publishing technology who have progressed through the industry, adapted to its changes, spotted new opportunities, and supported each other throughout.
Crossref has supported depositing metadata for preprints since 2016 and peer reviews since 2018. Now we are putting the two together, in fact we will permit peer reviews to be registered for any content type.
2020 has been a very challenging year, and we can all agree that everyone needs a break. Crossref will be providing very limited technical and membership support from 21st December to 3rd January to allow our staff to rest and recharge. We’ll be back on January 4th raring to answer your questions. Amanda explains more about why we made this decision.
If you’re using any deposit method except Metadata Manager, you can immediately move to step 2. If you’re using Metadata Manager to register content, you need to contact us as we need to take action to make the relevant fields available to you in Metadata Manager before you move onto step 2.
Create a Crossmark policy page and assign it a DOI: create a page on your website explaining that you are participating in the Crossmark service and have committed to maintaining version of record copies of content that display the Crossmark button. This page should be registered and have a DOI to enable persistent linking. It should explain your policies on corrections, retractions, withdrawals and other updates, and may contain definitions and explanations of any additional custom metadata fields that are being used. The page could also include links to other relevant policies such as author submission guidelines, and peer review guidelines. Learn more about creating a Crossmark policy page.
If you are already registering this additional metadata at the time you implement Crossmark, there is nothing more you need to do. If you start to register these metadata elements after you have set up Crossmark, they will automatically be put into the Crossmark box.
The Crossmark box has a section for you to show any additional non-bibliographic information about the content. You decide what to include here (you are not required to add anything). In this section, Crossmark participants often include publication history dates, details of the peer review process used, and links to supporting information.
Use Metadata Manager to add custom metadata, or use the assertion element in your XML.
The role of the @order attribute
@order is an optional attribute. If @order is absent, it will return stuff in the order you list it in deposit, but this is not guaranteed. If you want to be sure of the order, then you can use @order. Learn more about the Crossmark deposit elements (including what is optional) in the schema.
Step 1: Provide DOIs for items being corrected or updated. Crossmark updates should only be deposited for editorially significant changes - those that are likely to affect the interpretation or crediting of the work, and not for minor changes such as spelling corrections or formatting changes.
There are 12 defined types of accepted update within Crossmark:
If an update does not fall into one of these categories, it should instead be placed in the more information section of the pop-up box by being deposited as an assertion.
When deposited content corrects or updates earlier content, the DOI(s) of the corrected content must be supplied in the Crossmark metadata. See the Crossref unixref documentation section on updates for examples of how this is recorded in the Crossmark metadata.
When a correction is made in situ (that is, it replaces the earlier version completely), then the DOI of the corrected content will be the same as the DOI for the original Crossref deposit. In situ updates are not considered best practice as they obscure the scholarly record.
Step 2: Record the DOI in HTML metadata. You should ensure that the DOI is embedded in the head of the HTML metadata for all content to which Crossmark buttons are being applied as follows:
<meta name="dc.identifier" content="doi:10.5555/12345678"/>
Crossmark HTML widget. Please use the widget as specified below and do not alter the script or host the button locally.
There are a number of variations of the Crossmark button available so that you can choose one that fits well on your site. You can change the Crossmark button that is used simply by changing the src attribute of the img element to point to one of the following:
Step 4: Add Crossmark metadata to PDF content. At a minimum, this metadata must include the DOI of the content and the optional Crossmark domain(s). You may wish to use our open source tool pdfmark for embedding metadata in PDF files. The appropriate metadata is added to a PDF with the following command:
It may appear redundant to apply Crossmark elements both in their own Crossmark namespace as well in the pdfx namespace, but the latter is necessary to ensure the Crossmark elements appear in the PDF dictionary, a specific requirement for some search engines. Any metadata found in the pdfx namespace will be copied over to the document info dictionary. Simply make sure that Crossmark metadata is in the pdfx namespace in the XMP provided to the tool.
Step 5: Apply linked Crossmark buttons to your content - learn more about Crossmark button guidelines, including how and where to display the Crossmark button.
We have also created pdfstamp, an open-source command-line tool that makes it possible to add an image or stamp to any location on a PDF and to link that image to a chosen URL.
The link structure for Crossmark links from PDFs looks like this:
domain tells the Crossmark system what kind of static content the link is coming from, and will change for different static formats (such as epub)
date_stamp tells the Crossmark system the date on which a last Major Version of the PDF was generated. In most cases, this will be the date the article was published. However, when a member makes significant corrections to a PDF in-situ (no notice issued, and no new version of the work with a new DOI) then the date_stamp should reflect when the PDF was regenerated with the corrections. The system will then use the date_stamp in order to tell whether the reader needs to be alerted to updates or not. The date_stamp argument should be recorded in the form YYYY-MM-DD (learn more about ISO 8601).
Page owner: Laura J. Wilkinson | Last updated 2020-April-08