Template:Citation Style documentation/registration

Citations of online sources that require registration or a subscription are acceptable in Wikipedia as documented in Verifiability § Access to sources. As a courtesy to readers and other editors, editors should signal the access restrictions of the external links included in a citation.

Four access levels can be used:

• access indicator for named identifiers:
  • free: the source is free to read for anyone
• access indicators for url-holding parameters:
  • registration: a free registration is required to access the source
  • limited: there are other constraints (such as a cap on daily views) to freely access this source
  • subscription: the source is only accessible via a paid subscription ("paywall")

As there are often multiple external links with different access levels in the same citation, these values are attributed to a particular external link.

Access indicators for url-holding parameters

Sources linked by |url=, |article-url=, |chapter-url=, |contribution-url=, |entry-url=, |map-url=, and |section-url= are presumed to be free-to-read. When they are not free-to-read, editors should mark those sources with the matching access-indicator parameter so that an appropriate icon is included in the rendered citation. Because the sources linked by these url-holding parameters are presumed to be free-to-read, they may not be marked as free.

URL-holding and access-indicator parameters

URL	Access	Allowed keywords
|url=	|url-access=	registration limited subscription
|article-url=	|article-url-access=
|chapter-url=	|chapter-url-access=
|contribution-url=	|contribution-url-access=
|entry-url=	|entry-url-access=
|map-url=	|map-url-access=
|section-url=	|section-url-access=

Access indicator for named identifiers

Links inserted by named identifiers are presumed to lie behind a paywall or registration barrier – exceptions listed below. When they are free-to-read, editors should mark those sources with the matching access-indicator parameter so that an appropriate icon is included in the rendered citation. Because the sources linked by these named-identifier parameters are not presumed to be free-to-read, they may not be marked as limited, registration, or subscription.

Named-identifier and access-indicator parameters

Identifier	Access	Allowed keywords
|bibcode=	|bibcode-access=	free
|doi=	|doi-access=
|hdl=	|hdl-access=
|jstor=	|jstor-access=
|ol=	|ol-access=
|osti=	|osti-access=
|s2cid=	|s2cid-access=

Some named-identifiers are always free-to-read. For those named-identifiers there are no access-indicator parameters, the access level is automatically indicated by the template. These named identifiers are:

• |arxiv=
• |biorxiv=
• |citeseerx=
• |pmc=
• |rfc=
• |ssrn=

This guidance does not restrict linking to websites that are being used as sources to provide content in articles.