The following are basic data types for face markup. Face markup that appears in the title, subtitle, and original_language_title elements should be retained when depositing metadata. Face markup in other elements (e.g. small caps in author names) must be dropped. Face markup support includes bold (b), italic (i), underline (u), over-line (ovl), superscript (sup), subscript (sub), small caps (scp), and typewriter text (tt). See https://support.crossref.org/hc/en-us/articles/214532023 MathML may also be included using the 'mml' namespace prefix. content is "Inline" except that anchors shouldn't be nested Publisher generated ID that uniquely identifies the DOI submission batch. An integer representation of date and time that serves as a version number for the record that is being deposited, used to uniquely identify batch files and DOI values when a DOI has been updated one or more times. Information about the organization submitting DOI metadata to Crossref Name of the organization registering the DOIs. e-mail address to which batch success and/or error messages are sent. The organization responsible for the information being registered. The chapter, section, part, etc. number for a content item in a book. Unlike volume and edition_number, component_number should include any additional text that helps identify the type of component. The edition number of a book. edition_number should include only a number and not additional text such as "edition". For example, you should submit "3", not "third edition" or "3rd edition". Roman numerals are acceptable. The issue number or name in which an article is published. The issue number takes precedence over any other name. For example, if an issue has only a seasonal name, then the season should be listed in issue. The container for elements related directly to a DOI. The URI associated with a DOI. Container for item elements containing non-primary URIs associated with the item being registered. Collections are supported for the following (defined in the property attribute):

• list-based: Multiple Resolution, more info: https://www.crossref.org/education/content-registration/creating-and-managing-dois/multiple-resolution/
• country-based: more info: https://www.crossref.org/education/content-registration/creating-and-managing-dois/multiple-resolution/#00130
• crawler-based: for Similarity Check URLs, more info: https://www.crossref.org/education/similarity-check/participate/urls-for-new-deposits/
• text-mining: supply specific URLs for text and data mining, more info: https://www.crossref.org/education/retrieve-metadata/rest-api/text-and-data-mining-for-members/
• unspecified: can be used for additional URLs
• syndication: identifies resources to be used for syndication
• link-header: identifies resources to be used as an endpoint

A container used to associate a URI with the DOI being registered. NOTE: not currently supported. Use to flag references for distribution. "none" is the default and follows current protocol - references are only distributed to everyone if the prefix level permission is set, otherwise reference distribution is limited to the DOI owner. Setting the value to "query" releases references to anyone making a query request (this overrides any established prefix level permission). Value "any" allows bulk distribution to anyone (using a Crossref query account) using the OAI-PMH protocol, and also releases references to anyone making a query request. DOI for an entity being registered with Crossref. The ISBN assigned to an entity. The ISSN assigned to the title being registered. The volume number of a published journal, or the number of a printed volume for a book or conference proceedings. A list of articles, books, and other content cited by the item being registered citation is used to deposit each reference in the reference list of the item for which the DOI is being deposited. For details see: https://www.crossref.org/education/metadata-stewardship/maintaining-your-metadata/add-references/ Used to assign a unique ID to each reference that is deposited. We use this key value to track the specific reference query and will return this value along with the DOI in your query results. A citation to an item that is not structured with the Crossref citation model. 'unstructured_citation' supports deposit of references for which no structural information is available. Journal title in a citation. Book series title in a citation. Book volume title in a citation. First author in a citation. Year of publication in citation. Article title in a citation. article identifier or e-location id of the item Container element for CrossMark data. Some publishers encourage broad third party hosting of the publisher's content. Other publishers do not. And still others vary their policy depending on whether a particular article has been published under an OA policy or not. This boolean flag allows the publisher to indicate whether the Crossmarked content will only legitimately be updated on the Crossmark domain (true) or whether the publisher encourages updating the content on other sites as well (false). A DOI which points to a publisher's CrossMark policy document. Publishers might have different policies for different publications. Container element for crossmark_domain. A list of domains where the publisher maintains updates and corrections to their content. Minimally, one of these should include the Internet domain name of the publisher's web site(s), but the publisher might also decide to include 3rd party aggregators (e.g. Ebsco, IngentaConnect) or archives with which the publisher has agreements to update the content This should be a simple Internet domain name or subdomain name (e.g. www.psychoceramics.org or psychoceramics.org). It is used to identify when a referring URL is coming from a Crossmark domain. A "crossmark_domain" is made up of two subelements; a "domain" and a "filter". The filter is only needed for use in situations where content from multiple publishers/publications is on the same host with the same domain name (e.g. an aggregator) and one needs to use the referrer's URI "path" to further determine whether the content in a crossmark domain. A domain name or subdomain name (e.g. www.psychoceramics.org or psychoceramics.org). It is used to identify when a referring URL is coming from a Crossmark domain. The filter element is used to disambiguate content in situations where multiple publishers share the same host (e.g. when on an aggregated platform). It should contain a substring of the path that can be used to uniquely identify a publisher's or publication's content. For instance, using the string "alpsp" here would help the CrossMark system distinguish between ALPSP publications on the ingentaconnect host and other publications on the same host. A document might provide updates (e.g. corrections, clarifications, retractions) to several other documents. When this is the case, the DOIs of the documents that are being *updated* should be listed here. The DOI of the content being updated (e.g. corrected, retracted, etc.) In the CrossMark Terms and Conditions "updates" are defined as changes that are likely to "change the reader’s interpretation or crediting of the work." That is, *editorially significant* changes. "Updates" should not include minor changes to spelling, punctuation, formatting, etc. This attribute should be used to list the update type. Allowed update types are:

• addendum
• clarification
• correction
• corrigendum
• erratum
• expression_of_concern
• new_edition
• new_version
• partial_retraction
• removal
• retraction
• withdrawal

The date of the update will be displayed in the CrossMark dialog and can help the researcher easily tell whether they are likley to have seen the update. Publishers are encouraged to provided any non-bibliographical metadata that they feel might help the researcher evaluate and make better use of the content that the Crossmark record refers to. For example, publishers might want to provide funding information, clinical trial numbers, information about the peer-review process or a summary of the publication history of the document. An assertion is a piece of custom, non-bibliographic metadata that the publisher is asserting about the content to which the Crossmark refers. If the publisher wants to provide a further explanation of what the particular "assertion" means, they can link to such an explanation by providing an appropriate url on the "explanation" attribute. This is the human-readable form of the "group_name" attribute. This is what will be displayed in the group headings on the Crossmark metadata record dialog. Some assertions could be logically "grouped" together in the CrossMark dialog. For instance, if the publisher is recording several pieces of metadata related to funding sources (source name, percentage, grant number), they may want to make sure that these three assertions are grouped next to each-other in the CrossMark dialog. The group_name attribute is the machine-readable value that will be used for grouping such assertions. This is the human-readable version of the name attribute which will be displayed in the CrossMark dialog. If this attribute is missing, then the value of the assertion will *not* be displayed in the dialog. Publishers may want to "hide" assertions this way in cases where the assertion value is too large or too complex to display in the dialog, but where the assertion is nonetheless valuable enough to include in API queries and metadata dumps (e.g. detailed licensing terms) This is the machine-readable name of the assertion. Use the "label" attribute to provide a human-readable version of the name. The publisher may want to control the order in which assertions are displayed to the user in the CrossMark dialog. All assertions will be sorted by this element if it is present. A wrapper for designators or other primary identifiers for a standard. Designator or other primary identifier for the standard being deposited. Provides for defining a DOI for a broad grouping of standards. Provides for defining a DOI for a set of standards (sometimes know as truncated form). Provides for defining a DOI for a group of closely related standard documents (undated form is a stem for any dated form) Designator for standard being replaced by the standard being deposited. Designator for standard from which the current deposit is adopted. Designator for the previous revision of the standard being deposited. (note: use alt_as_published for revisions within designators having common stem) A wrapper for standards body information. Name of the standards organization / publisher. Acronym for standards body. A wrapper for Scholarly Sharing Network (SCN) policy information A group of related SCN policies An individual SCN policy Media / mime types for component format. For mime types refer to http://www.iana.org/assignments/media-types/ Language attributes are based on ISO 639 First page number of an item. Last page number of an item. When an item has non-contiguous page information, capture the first page range in first_page and last_page. Any additional page information should be captured in other_pages.