Supplementary Materials

Supplementary, or supplemental, material is defined as additional data that is non-integral to the understanding of the article (where “non-integral” means that the article can be fully understood without the need to see the additional supplemental material). Supplementary material is used to add detail, background, or context to an article by providing, for example, multimedia objects such as audio and video clips, tables or figures, raw data in a spreadsheet, or a separate PDF file containing additional information.

When an article has supplementary material the article may contain a statement to alert readers about the existence of the supplementary material and indicate where to access the supplementary material online.

In the online article, supplementary files are presented to readers as a link to a file download with a title and an optional description for each file.

For current content, supplementary files are stored in CATS and XML tagging should be added based on supplementary file information provided by CATS.

For converted or digitized content that was previously published, XML tagging should be added based on the supplementary files that are present and the supplementary files should be included in the zip package with the article XML.

• File Types and Size Limits
• File and Folder Naming Convention
• Supplementary Material XML Tagging
• MIME type (IANA media type)
• Supplementary Material Section

File Types and Size Limits

There is no restriction on file types that can be used for supplementary material, however, common file types include documents (.docx, .pdf), images (.jpeg, .tif), multimedia (.mp4, .mp3, .mpeg, .wmv) and spreadsheets (.csv, .xlsx).

Often, supplementary material will be provided as a collection of documents and files within a .zip file. In these cases, the .zip file itself should be considered the supplementary material and should be referenced as such within the XML.

Strictly speaking, there is no file-size limit for a single supplemental file, however, we advise authors to keep file sizes as small as possible given that the file must be downloaded by readers in order to access the content. If a supplemental file exceeds the limit of 250MB, then the following validation warning will be triggered:

“Supplemental file [FILENAME] exceeds the 250MB advisory limit and may result in excessive download times. Consider reducing the file size.”

File and Folder Naming Convention

Supplemental files follow the naming convention below.

Example file name: BATC_A_123456_SM0001.zip

Pattern: {journal acronym}_A_{article id}_SM{supplementary file id].{ext}

For current content, supplemental file names and supplementary file IDs will be stored in CATS and supplied in CATS data. For scanned (retro) and converted content, files should be named according to the conventions above. Each supplemental file should be given a supplementary file ID, which should begin with “SM” followed by a 4-digit number that is unique within the article.

For scanned or converted content, each supplemental file should be placed in an article-level folder named “suppl”. Each supplemental file referenced within the XML must be present within the article-level “suppl” folder. Each supplemental file present within the article-level “suppl” folder must be referenced within the article XML.

For more information about the naming convention see File and ID Naming Conventions.

Supplementary Material XML Tagging

Each supplementary file associated with a manuscript requires a corresponding reference in the article XML using a <supplementary-material> element placed within <article-meta>. The <supplementary-material> element has the following XML attributes and elements:

The <supplementary-material> element may contain a <caption> child element. Within <caption> a <title> must be included followed by an optional description captured within <p> tags. The <title> of each file will be supplied in CATS data and is limited to 256 bytes (characters) in length. The <title> should contain a descriptive title of the file (E.g. Supplemental Video 1), and it shouldn’t contain the file name itself. The optional description of each file will also be supplied in CATS data and does not have a character limit. If the supplemental file title for scanned (retro) and converted content is not known, the generic title of “Supplemental Material” should be used.

Full <supplementary-material> tagging example:

<supplementary-material id="SM0001" mimetype="application" mime-subtype="pdf" xlink:href="TBEE_A_1602022_SM0001.pdf"> 
<caption> 
<title>Supplemental Appendix 1</title> 
<p>This appendix has been provided by the authors to give readers additional information about their work.</p> 
</caption> 
</supplementary-material> 

MIME type (IANA media type)

The @mimetype and @mime-subtype attributes must be populated with the correct IANA Media Type that corresponds to the file extension of the file that is being referenced. The table below lists mime type and subtype values for several common file formats.

A full list of mime types can be found at the IANA official register of media types here: https://www.iana.org/assignments/media-types/media-types.xhtml

Supplementary Material Section

Depending on the given PDF style for a journal, some articles that have supplementary material will have a special section added near the end of the article or a footnote on the article opening page. This special section usually has a title like “Supplemental Material” or “Supplementary Data” or an icon and contains a link directing readers to the supplementary material.

This special section can be generated automatically based on the presence of <supplementary-material> tagging in <article-meta>.

If this special section is tagged in the XML it should be placed within <back> and have an attribute @sec-type="supplementary-material" placed on the <sec> element. The link to find the supplementary material online should be a DOI link to the article. The URL should be formed by concatenating https://doi.org/ with the article’s DOI. For example:

<sec id="s0006" sec-type="supplementary-material"> 
<title>Supplemental Material</title> 
<p>Supplemental data for this article can be accessed at <ext-link ext-link-type="uri" xlink:href="https://doi.org/10.4161/2162402X.2014.992749">https://doi.org/10.4161/2162402X.2014.992749</ext-link>.</p>
</caption> 
</sec> 

The text that describes where to find supplementary material should include the link in full using a persistent DOI URL.

Take care that the text and the link will be useful to to a reader who may be reading the article in print format or on a third-party website. Text such as “on the publisher’s website” provides the reader with some guidance, but text such as “here” provides the reader with no help whatsoever and also goes against accessibility guidelines. For instance, the following example should be avoided:

“Supplemental data for this article can be accessed here.”

When processing articles that have previously been published it might not be possible, nor permitted, to alter outdated text that incorrectly describes where to find supplementary material or has a broken URL. In such cases, the link may be updated in the @xlink:href attribute using a correct persistent DOI URL without altering the text that is displayed.