diff --git a/doc/install/requirements.md b/doc/install/requirements.md
index 13a6a1c68adbf14def977e402aec893f56946591..dcc6d75724eb298d9bef3934c03804ea34168726 100644
--- a/doc/install/requirements.md
+++ b/doc/install/requirements.md
@@ -36,7 +36,7 @@ Please consider using a virtual machine to run GitLab.
 GitLab requires Ruby (MRI) 2.3. Support for Ruby versions below 2.3 (2.1, 2.2) will stop with GitLab 8.13.
 
 You will have to use the standard MRI implementation of Ruby.
-We love [JRuby](http://jruby.org/) and [Rubinius](http://rubini.us/) but GitLab
+We love [JRuby](https://www.jruby.org/) and [Rubinius](https://rubinius.com) but GitLab
 needs several Gems that have native extensions.
 
 ## Hardware requirements
diff --git a/doc/integration/auth0.md b/doc/integration/auth0.md
index a75836a915a54f4cafb74ef6abeeab0ad40bd04e..bccaeec37065ea925dacc531fb137db3531815bb 100644
--- a/doc/integration/auth0.md
+++ b/doc/integration/auth0.md
@@ -3,7 +3,7 @@
 To enable the Auth0 OmniAuth provider, you must create an Auth0 account, and an
 application.
 
-1. Sign in to the [Auth0 Console](https://manage.auth0.com). If you need to
+1. Sign in to the [Auth0 Console](https://auth0.com/auth/login). If you need to
 create an account, you can do so at the same link.
 
 1. Select "New App/API".
diff --git a/doc/user/project/import/clearcase.md b/doc/user/project/import/clearcase.md
index f23623ed4857ab69c4ad220591ec39cf82b4fd32..89a9f7da852d9b7174b08b6ac22cb7f99ce87a7b 100644
--- a/doc/user/project/import/clearcase.md
+++ b/doc/user/project/import/clearcase.md
@@ -1,6 +1,6 @@
 # Migrating from ClearCase
 
-[ClearCase](https://www-03.ibm.com/software/products/en/clearcase/) is a set of
+[ClearCase](https://www.ibm.com/us-en/marketplace/rational-clearcase) is a set of
 tools developed by IBM which also include a centralized version control system
 similar to Git.
 
diff --git a/doc/user/project/integrations/mattermost.md b/doc/user/project/integrations/mattermost.md
index 89de1fe4dcb68adb2963a092c0bb967cfea01f6e..ed4367c1135f511aac137e76b587a0da2e4152a1 100644
--- a/doc/user/project/integrations/mattermost.md
+++ b/doc/user/project/integrations/mattermost.md
@@ -4,9 +4,9 @@
 
 To enable Mattermost integration you must create an incoming webhook integration:
 
-1. Sign in to your Mattermost instance
-1. Visit incoming webhooks, that will be something like: https://mattermost.example/your_team_name/integrations/incoming_webhooks/add
-1. Choose a display name, description and channel, those can be overridden on GitLab
+1. Sign in to your Mattermost instance.
+1. Visit incoming webhooks, that will be something like: `https://mattermost.example.com/your_team_name/integrations/incoming_webhooks/add`.
+1. Choose a display name, description and channel, those can be overridden on GitLab.
 1. Save it, copy the **Webhook URL**, we'll need this later for GitLab.
 
 There might be some cases that Incoming Webhooks are blocked by admin, ask your mattermost admin to enable