The following links provide helpful additional information on user authentication and authorization.

• http://www.dushyantgill.com/blog/2014/12/10/roles-based-access-control-in-cloud-applications-using-azure-ad/
• https://azure.microsoft.com/nl-nl/documentation/articles/active-directory-integrating-applications/
• https://azure.microsoft.com/nl-nl/documentation/articles/active-directory-authentication-protocols/
• https://msdn.microsoft.com/office/office365/howto/add-common-consent-manually#bk_RegisterServerApp
• https://apps.dev.microsoft.com/#/appList
• https://console.developers.google.com/
• https://developers.google.com/identity/protocols/OAuth2
• http://openid.net/specs/openid-connect-core-1_0.html