Editing Template:Citation Style documentation/registration

Citations of online sources that require registration or a subscription are acceptable in Wikipedia as documented in [[WP:PAYWALL|Verifiability – Access to sources]]. As a courtesy to readers and other editors, editors can signal the access restrictions of the external links included in a citation.

Four access levels can be used:
* [[File:Lock-green.svg|9px|link=|alt=Freely accessible|Freely accessible]] <code>free</code>: the source is free to read for anyone (this applies in particular to articles in open access)
* [[File:Lock-blue-alt-2.svg|9px|link=|alt=Free registration required|Free registration required]] <code>registration</code>: a free registration is required to access the source
* [[File:Lock-blue-alt-2.svg|9px|link=|alt=Free access subject to limited trial, subscription normally required|Free access subject to limited trial, subscription normally required]] <code>limited</code>: there are other constraints (such as a cap on daily views) to freely access this source
* [[File:Lock-red-alt.svg|9px|link=|alt=Paid subscription required|Paid subscription required]] <code>subscription</code>: 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 level of {{para|url}}=====
Links inserted with {{para|url}} are expected to be free to read by default. If not, editors can use one of
* {{para|url-access|subscription}}
* {{para|url-access|registration}}
* {{para|url-access|limited}}
to indicate the relevant access restriction.

=====Access level of identifiers=====
Links inserted by identifiers such as {{para|doi}} are not expected to offer a free full text by default. If they do, editors can use {{para|doi-access|free}} (in the case of {{para|doi}}) to indicate the relevant access level. The following identifiers are supported:
:* {{para|bibcode}} with {{para|bibcode-access|free}}
:* {{para|doi}} with {{para|doi-access|free}}
:* {{para|hdl}} with {{para|hdl-access|free}}
:* {{para|jstor}} with {{para|jstor-access|free}}
:* {{para|ol}} with {{para|ol-access|free}}
:* {{para|osti}} with {{para|osti-access|free}}

Some identifiers always link to free full texts. In this case, the access level is automatically indicated by the template. This is the case for {{para|arxiv}}, {{para|biorxiv}}, {{para|citeseerx}}, {{para|pmc}}, {{para|rfc}} and {{para|ssrn}}.

=====Ambiguous access parameters=====
The parameters {{para|registration|yes}} and {{para|subscription|yes}} can also be used to indicate the access level of a citation. However, they do not indicate which link they apply to, so editors are encouraged to use {{para|url-access|registration}} and {{para|url-access|subscription}} instead, when the restriction applies to {{para|url}}. If the restriction applies to an identifier, these parameters should be omitted.

These parameters add a link note to the end of the citation:
* '''registration''': For online sources that require registration, set {{para|registration|yes}} (or <code>y</code>, or <code>true</code>); superseded by '''subscription''' if both are set.
* '''subscription''': For online sources that require a subscription, set {{para|subscription|yes}} (or <code>y</code>, or <code>true</code>); supersedes '''registration''' if both are set.
Setting {{para|registration}} or {{para|subscription}} to any value other than <code>y</code>, <code>yes</code>, or <code>true</code> will generate an error message.