[1] Final: OpenID Connect Core 1.0 incorporating errata set 1 (2014-11-09 04:00:29 +09:00 版) http://openid.net/specs/openid-connect-core-1_0.html#OfflineAccess

[2] OpenID Connect (OAuth 2.0 for Login) - Google Accounts Authentication and Authorization — Google Developers (2015-02-04 03:07:27 +09:00 版) https://developers.google.com/accounts/docs/OpenIDConnect#refresh-tokens

[3] OpenID Connect (OAuth 2.0 for Login) - Google Accounts Authentication and Authorization — Google Developers (2015-02-04 03:07:27 +09:00 版) https://developers.google.com/accounts/docs/OpenIDConnect#authenticationuriparameters

The allowed values are offline and online. The effect is documented in Offline Access; if an access token is being requested, the client does not receive a refresh token unless offline is specified.

[4] Using OAuth 2.0 for Web Server Applications - Google Accounts Authentication and Authorization — Google Developers (2014-12-05 11:52:25 +09:00 版) https://developers.google.com/accounts/docs/OAuth2WebServer#offline