Release Entity Reference


  • title (string, required): the display title of the release. May include subtitle.
  • subtitle (string): intended only to be used primarily with books, not journal articles. Subtitle may also be appended to the title instead of populating this field.
  • original_title (string): the full original language title, if title is translated
  • work_id (fatcat identifier; required): the (single) work that this release is grouped under. If not specified in a creation (POST) action, the API will auto-generate a work.
  • container_id (fatcat identifier): a (single) container that this release is part of. When expanded the container field contains the full container entity.
  • release_type (string, controlled set): represents the medium or form-factor of this release; eg, "book" versus "journal article". Not necessarily the same across all releases of a work. See definitions below.
  • release_stage (string, controlled set): represents the publishing/review lifecycle status of this particular release of the work. See definitions below.
  • release_date (string, ISO date format): when this release was first made publicly available. Blank if only year is known.
  • release_year (integer): year when this release was first made publicly available; should match release_date if both are known.
  • withdrawn_status (optional, string, controlled set):
  • withdrawn_date (optional, string, ISO date format): when this release was withdrawn. Blank if only year is known.
  • withdrawn_year (optional, integer): year when this release was withdrawn; should match withdrawn_date if both are known.
  • ext_ids (key/value object of string-to-string mappings): external identifiers. At least an empty ext_ids object is always required for release entities, so individual identifiers can be accessed directly.
  • volume (string): optionally, stores the specific volume of a serial publication this release was published in. type: string
  • issue (string): optionally, stores the specific issue of a serial publication this release was published in.
  • pages (string): the pages (within a volume/issue of a publication) that this release can be looked up under. This is a free-form string, and could represent the first page, a range of pages, or even prefix pages (like "xii-xxx").
  • version (string): optionally, describes distinguishes this release version from others. Generally a number, software-style version, or other short/slug string, not a freeform description. Book "edition" descriptions can also go in an edition extra field. Often used in conjunction with external identifiers. If you're not certain, don't use this field!
  • number (string): an inherent identifier for this release (or work), often part of the title. For example, standards numbers, technical memo numbers, book series number, etc. Not a book chapter number however (which can be stored in extra). Depending on field or series-specific norms, the number may be stored here, in the title, or in both fields.
  • publisher (string): name of the publishing entity. This does not need to be populated if the associated container entity has the publisher field set, though it is acceptable to duplicate, as the publishing entity of a container may differ over time. Should be set for singleton releases, like books.
  • language (string, slug): the primary language used in this particular release of the work. Only a single language can be specified; additional languages can be stored in "extra" metadata (TODO: which field?). This field should be a valid RFC1766/ISO639 language code (two letters). AKA, a controlled vocabulary, not a free-form name of the language.
  • license_slug (string, slug): the license of this release. Usually a creative commons short code (eg, CC-BY), though a small number of other short names for publisher-specific licenses are included (TODO: list these).
  • contribs (array of objects): an array of authorship and other creator contributions to this release. Contribution fields include:
    • index (integer, optional): the (zero-indexed) order of this author. Authorship order has significance in many fields. Non-author contributions (illustration, translation, editorship) may or may not be ordered, depending on context, but index numbers should be unique per release (aka, there should not be "first author" and "first translator")
    • creator_id (identifier): if known, a reference to a specific creator
    • raw_name (string): the name of the contributor, as attributed in the text of this work. If the creator_id is linked, this may be different from the display_name; if a creator is not linked, this field is particularly important. Syntax and name order is not specified, but most often will be "display order", not index/alphabetical (in Western tradition, surname followed by given name).
    • role (string, of a set): the type of contribution, from a controlled vocabulary. TODO: vocabulary needs review.
    • extra (string): additional context can go here. For example, author affiliation, "this is the corresponding author", etc.
  • refs (array of ident strings): references (aka, citations) to other releases. References can only be linked to a specific target release (not a work), though it may be ambiguous which release of a work is being referenced if the citation is not specific enough. IMPORTANT: release refs are distinct from the reference graph API. Reference fields include:
    • index (integer, optional): reference lists and bibliographies almost always have an implicit order. Zero-indexed. Note that this is distinct from the key field.
    • target_release_id (fatcat identifier): if known, and the release exists, a cross-reference to the Fatcat entity
    • extra (JSON, optional): additional citation format metadata can be stored here, particularly if the citation schema does not align. Common fields might be "volume", "authors", "issue", "publisher", "url", and external identifiers ("doi", "isbn13").
    • key (string): works often reference works with a short slug or index number, which can be captured here. For example, "[BROWN2017]". Keys generally supersede the index field, though both can/should be supplied.
    • year (integer): year of publication of the cited release.
    • container_title (string): if applicable, the name of the container of the release being cited, as written in the citation (usually an abbreviation).
    • title (string): the title of the work/release being cited, as written.
    • locator (string): a more specific reference into the work/release being cited, for example the page number(s). For web reference, store the URL in "extra", not here.
  • abstracts (array of objects): see below
    • sha1 (string, hex, required): reference to the abstract content (string). Example: "3f242a192acc258bdfdb151943419437f440c313"
    • content (string): The abstract raw content itself. Example: <jats:p>Some abstract thing goes here</jats:p>
    • mimetype (string): not formally required, but should effectively always get set. text/plain if the abstract doesn't have a structured format
    • lang (string, controlled set): the human language this abstract is in. See the lang field of release for format and vocabulary.

External Identifiers (ext_ids)

The ext_ids object name-spaces external identifiers and makes it easier to add new identifiers to the schema in the future.

Many identifier fields must match an internal regex (string syntax constraint) to ensure they are properly formatted, though these checks aren't always complete or correct in more obscure cases.

  • doi (string): full DOI number, lower-case. Example: "10.1234/abcde.789". See section below for more about DOIs specifically
  • wikidata_qid (string): external identifier for Wikidata entities. These are integers prefixed with "Q", like "Q4321". Each release entity can be associated with at most one Wikidata entity (this field is not an array), and Wikidata entities should be associated with at most a single release. In the future it may be possible to associate Wikidata entities with work entities instead.
  • isbn13 (string): external identifier for books. ISBN-9 and other formats should be converted to canonical ISBN-13.
  • pmid (string): external identifier for the PubMed database. These are bare integers, but stored in a string format.
  • pmcid (string): external identifier for PubMed Central database. These are integers prefixed with "PMC" (upper case), like "PMC4321". Versioned PMCIDs can also be stored (eg, "PMC4321.1"; future clarification of whether versions should always be stored will be needed.
  • core (string): external identifier for the CORE open access aggregator. Not used much in practice. These identifiers are integers, but stored in string format.
  • arxiv (string): external identifier to a (version-specific) work. For releases, must always include the vN suffix (eg, v3).
  • jstor (string): external identifier for works in JSTOR which do not have a valid registered DOI.
  • ark (string): ARK identifier.
  • mag (DEPRECATED; string): Microsoft Academic Graph (MAG) identifier. As of December 2021, no entities in the catalog have a value for this field.
  • doaj (string): DOAJ article-level identifier
  • dblp (string): dblp article-level identifier
  • oai (string): OAI-PMH record id. Only use if no other identifier is available
  • hdl (string): identifier. While DOIs are technically handles, do not put DOIs in this field. Handles are normalized to lower-case in the catalog (server-side).

extra Fields

  • crossref (object), for extra crossref-specific metadata
    • subject (array of strings) for subject/category of content
    • type (string) raw/original Crossref type
    • alternative-id (array of strings)
    • archive (array of strings), indicating preservation services deposited
    • funder (object/dictionary)
  • aliases (array of strings) for additional titles this release might be known by
  • container_name (string) if not matched to a container entity
  • group-title (string) for releases within an collection/group
  • translation_of (release identifier) if this release is a translation of another (usually under the same work)
  • superceded (boolean) if there is another release under the same work that should be referenced/indicated instead. Intended as a temporary hint until proper work-based search is implemented. As an example use, all arxiv release versions except for the most recent get this set.
  • is_work_alias (boolean): if true, then this release is an alias or pointer to the entire work, or the most recent version of the work. For example, some data repositories have separate DOIs for each version of the dataset, then an additional DOI that points to the "latest" version/DOI.

release_type Vocabulary

This vocabulary is based on the CSL types, with a small number of (proposed) extensions:

  • article-magazine
  • article-journal, including pre-prints and working papers
  • book
  • chapter is allowed as they are frequently referenced and read independent of the entire book. The data model does not currently support linking a subset of a release to an entity representing the entire release. The release/work/file distinctions should not be used to group multiple chapters under a single work; a book chapter can be it's own work. A paper which is republished as a chapter (eg, in a collection, or "edited" book) can have both releases under one work. The criteria of whether to "split" a book and have release entities for each chapter is whether the chapter has been cited/reference as such.
  • dataset
  • entry, which can be used for generic web resources like question/answer site entries.
  • entry-encyclopedia
  • manuscript
  • paper-conference
  • patent
  • post-weblog for blog entries
  • report
  • review, for things like book reviews, not the "literature review" form of article-journal, nor peer reviews (see peer_review). Note review-book for book reviews specifically.
  • speech can be used for eg, slides and recorded conference presentations themselves, as distinct from paper-conference
  • thesis
  • webpage
  • peer_review (fatcat extension)
  • software (fatcat extension)
  • standard (fatcat extension), for technical standards like RFCs
  • abstract (fatcat extension), for releases that are only an abstract of a larger work. In particular, translations. Many are granted DOIs.
  • editorial (custom extension) for columns, "in this issue", and other content published along peer-reviewed content in journals. Many are granted DOIs.
  • letter for "letters to the editor", "authors respond", and sub-article-length published content. Many are granted DOIs.
  • stub (fatcat extension) for releases which have notable external identifiers, and thus are included "for completeness", but don't seem to represent a "full work".
  • component (fatcat extension) for sub-components of a full paper or other work. Eg, tables, or individual files as part of a dataset.

An example of a stub might be a paper that gets an extra DOI by accident; the primary DOI should be a full release, and the accidental DOI can be a stub release under the same work. stub releases shouldn't be considered full releases when counting or aggregating (though if technically difficult this may not always be implemented). Other things that can be categorized as stubs (which seem to often end up mis-categorized as full articles in bibliographic databases):

  • commercial advertisements
  • "trap" or "honey pot" works, which are fakes included in databases to detect re-publishing without attribution
  • "This page is intentionally blank"
  • "About the author", "About the editors", "About the cover"
  • "Acknowledgments"
  • "Notices"

All other CSL types are also allowed, though they are mostly out of scope:

  • article (generic; should usually be some other type)
  • article-newspaper
  • bill
  • broadcast
  • entry-dictionary
  • figure
  • graphic
  • interview
  • legislation
  • legal_case
  • map
  • motion_picture
  • musical_score
  • pamphlet
  • personal_communication
  • post
  • review-book
  • song
  • treaty

For the purpose of statistics, the following release types are considered "papers":

  • article
  • article-journal
  • chapter
  • paper-conference
  • thesis

release_stage Vocabulary

These roughly follow the DRIVER publication version guidelines, with the addition of a retracted status.

  • draft is an early version of a work which is not considered for peer review. Sometimes these are posted to websites or repositories for early comments and feedback.
  • submitted is the version that was submitted for publication. Also known as "pre-print", "pre-review", "under review". Note that this doesn't imply that the work was every actually submitted, reviewed, or accepted for publication, just that this is the version that "would be". Most versions in pre-print repositories are likely to have this status.
  • accepted is a version that has undergone peer review and accepted for published, but has not gone through any publisher copy editing or re-formatting. Also known as "post-print", "author's manuscript", "publisher's proof".
  • published is the version that the publisher distributes. May include minor (gramatical, typographical, broken link, aesthetic) corrections. Also known as "version of record", "final publication version", "archival copy".
  • updated: post-publication significant updates (considered a separate release in Fatcat). Also known as "correction" (in the context of either a published "correction notice", or the full new version)
  • retraction for post-publication retraction notices (should be a release under the same work as the published release)

Note that in the case of a retraction, the original publication does not get state retracted, only the retraction notice does. The original publication does get a withdrawn_status metadata field set.

When blank, indicates status isn't known, and wasn't inferred at creation time. Can often be interpreted as published, but be careful!

withdrawn_status Vocabulary

Don't know of an existing controlled vocabulary for things like retractions or other reasons for marking papers as removed from publication, so invented my own. These labels should be considered experimental and subject to change.

Note that some of these will apply more to pre-print servers or publishing accidents, and don't necessarily make sense as a formal change of status for a print journal publication.

Any value at all indicates that the release should be considered "no longer published by the publisher or primary host", which could mean different things in different contexts. As some concrete examples, works are often accidentally generated a duplicate DOI; physics papers have been taken down in response to government order under national security justifications; papers have been withdrawn for public health reasons (above and beyond any academic-style retraction); entire journals may be found to be predatory and pulled from circulation; individual papers may be retracted by authors if a serious mistake or error is found; an author's entire publication history may be retracted in cases of serious academic misconduct or fraud.

  • withdrawn is generic: the work is no longer available from the original publisher. There may be no reason, or the reason may not be known yet.
  • retracted for when a work is formally retracted, usually accompanied by a retraction notice (a separate release under the same work). Note that the retraction itself should not have a withdrawn_status.
  • concern for when publishers release an "expression of concern", often indicating that the work is not reliable in some way, but not yet formally retracted. In this case the original work is probably still available, but should be marked as suspect. This is not the same as presence of errata.
  • safety for works pulled for public health or human safety concerns.
  • national-security for works pulled over national security concerns.
  • spam for content that is considered spam (eg, bogus pre-print or repository submissions). Not to be confused with advertisements or product reviews in journals.

contribs.role Vocabulary

  • author
  • translator
  • illustrator
  • editor

All other CSL role types are also allowed, though are mostly out of scope for Fatcat:

  • collection-editor
  • composer
  • container-author
  • director
  • editorial-director
  • editortranslator
  • interviewer
  • original-author
  • recipient
  • reviewed-author

If blank, indicates that type of contribution is not known; this can often be interpreted as authorship.

More About DOIs

All DOIs stored in an entity column should be registered (aka, should be resolvable from Invalid identifiers may be cleaned up or removed by bots.

DOIs should always be stored and transferred in lower-case form. Note that there are almost no other constraints on DOIs (and handles in general): they may have multiple forward slashes, whitespace, of arbitrary length, etc. Crossref has a number of examples of such "valid" but frustratingly formatted strings.

In the Fatcat ontology, DOIs and release entities are one-to-one.

It is the intention to automatically (via bot) create a Fatcat release for every Crossref-registered DOI from an allowlist of media types ("journal-article" etc, but not all), and it would be desirable to auto-create entities for in-scope publications from all registrars. It is not the intention to auto-create a release for every registered DOI. In particular, "sub-component" DOIs (eg, for an individual figure or table from a publication) aren't currently auto-created, but could be stored in "extra" metadata, or on a case-by-case basis.