diff --git a/docs.it4i/general/accessing-the-clusters/graphical-user-interface/vnc.md b/docs.it4i/general/accessing-the-clusters/graphical-user-interface/vnc.md
index 864160517d3edcf3d08d73ecef9c1b9efc963d41..5db8abf2c7214f1f5373286841b81b1be3ffc48a 100644
--- a/docs.it4i/general/accessing-the-clusters/graphical-user-interface/vnc.md
+++ b/docs.it4i/general/accessing-the-clusters/graphical-user-interface/vnc.md
@@ -1,10 +1,10 @@
 # VNC
 
-The **Virtual Network Computing** (**VNC**) is a graphical [desktop sharing](http://en.wikipedia.org/wiki/Desktop_sharing "Desktop sharing") system that uses the [Remote Frame Buffer protocol (RFB)](http://en.wikipedia.org/wiki/RFB_protocol "RFB protocol") to remotely control another [computer](http://en.wikipedia.org/wiki/Computer "Computer"). It transmits the [keyboard](http://en.wikipedia.org/wiki/Computer_keyboard "Computer keyboard") and [mouse](http://en.wikipedia.org/wiki/Computer_mouse") events from one computer to another, relaying the graphical [screen](http://en.wikipedia.org/wiki/Computer_screen "Computer screen") updates back in the other direction, over a [network](http://en.wikipedia.org/wiki/Computer_network "Computer network").
+The **Virtual Network Computing** (**VNC**) is a graphical [desktop sharing][a] system that uses the [Remote Frame Buffer protocol (RFB)][b] to remotely control another [computer][c]). It transmits the [keyboard][d] and [mouse][e] events from one computer to another, relaying the graphical [screen][f] updates back in the other direction, over a [network][g].
 
-Vnc-based connections are usually faster (require less network bandwidth) then [X11](general/accessing-the-clusters/graphical-user-interface/x-window-system) applications forwarded directly through ssh.
+Vnc-based connections are usually faster (require less network bandwidth) then [X11][1] applications forwarded directly through ssh.
 
-The recommended clients are [TightVNC](http://www.tightvnc.com) or [TigerVNC](http://sourceforge.net/apps/mediawiki/tigervnc/index.php?title=Main_Page) (free, open source, available for almost any platform).
+The recommended clients are [TightVNC][h] or [TigerVNC][i] (free, open source, available for almost any platform).
 
 In this chapter we show how to create an underlying ssh tunnel from your client machine to one of our login nodes. Then, how to start your own vnc server on our login node and finally how to connect to your vnc server via the encrypted ssh tunnel.
 
@@ -24,7 +24,7 @@ Verify:
 !!! note
     To access VNC a local vncserver must be started first and also a tunnel using SSH port forwarding must be established.
 
-[See below](#linuxmac-os-example-of-creating-a-tunnel) for the details on SSH tunnels.
+[See below][2] for the details on SSH tunnels.
 
 You should start by **choosing your display number**.
 To choose free one, you should check currently occupied display numbers - list them using command:
@@ -78,7 +78,7 @@ username :102
 !!! note
     The VNC server runs on port 59xx, where xx is the display number. So, you get your port number simply as 5900 + display number, in our example 5900 + 61 = 5961. Another example for display number 102 is calculation of TCP port 5900 + 102 = 6002 but be aware, that TCP ports above 6000 are often used by X11. **Please, calculate your own port number and use it instead of 5961 from examples below!**
 
-To access the VNC server you have to create a tunnel between the login node using TCP port 5961 and your machine using a free TCP port (for simplicity the very same) in next step. See examples for [Linux/Mac OS](#linuxmac-os-example-of-creating-a-tunnel) and [Windows](#windows-example-of-creating-a-tunnel).
+To access the VNC server you have to create a tunnel between the login node using TCP port 5961 and your machine using a free TCP port (for simplicity the very same) in next step. See examples for [Linux/Mac OS][2] and [Windows][3].
 
 !!! note
     The tunnel must point to the same login node where you launched the VNC server, eg. login2. If you use just cluster-name.it4i.cz, the tunnel might point to a different node due to DNS round robin.
@@ -145,7 +145,7 @@ Fill the Source port and Destination fields. **Do not forget to click the Add bu
 
 ### WSL (Bash on Windows)
 
-[Windows Subsystem for Linux](http://docs.microsoft.com/en-us/windows/wsl) is another way to run Linux software in a Windows environment.
+[Windows Subsystem for Linux][j] is another way to run Linux software in a Windows environment.
 
 At your machine, create the tunnel:
 
@@ -214,7 +214,7 @@ Or this way:
 ```
 
 !!! note
-    Do not forget to terminate also SSH tunnel, if it was used. Look on end of [this section](#linuxmac-os-example-of-creating-a-tunnel) for the details.
+    Do not forget to terminate also SSH tunnel, if it was used. Look on end of [this section][2] for the details.
 
 ## GUI Applications on Compute Nodes Over VNC
 
@@ -230,7 +230,7 @@ Allow incoming X11 graphics from the compute nodes at the login node:
 $ xhost +
 ```
 
-Get an interactive session on a compute node (for more detailed info [look here](anselm/job-submission-and-execution/)). Use the **-v DISPLAY** option to propagate the DISPLAY on the compute node. In this example, we want a complete node (16 cores in this example) from the production queue:
+Get an interactive session on a compute node (for more detailed info [look here][4]). Use the **-v DISPLAY** option to propagate the DISPLAY on the compute node. In this example, we want a complete node (16 cores in this example) from the production queue:
 
 ```console
 $ qsub -I -v DISPLAY=$(uname -n):$(echo $DISPLAY | cut -d ':' -f 2) -A PROJECT_ID -q qprod -l select=1:ncpus=16
@@ -245,3 +245,20 @@ $ xterm
 Example described above:
 
 ![](../../../img/gnome-compute-nodes-over-vnc.png)
+
+
+[a]: http://en.wikipedia.org/wiki/Desktop_sharing
+[b]: http://en.wikipedia.org/wiki/RFB_protocol
+[c]: http://en.wikipedia.org/wiki/Computer
+[d]: http://en.wikipedia.org/wiki/Computer_keyboard
+[e]: http://en.wikipedia.org/wiki/Computer_mouse
+[f]: http://en.wikipedia.org/wiki/Computer_screen
+[g]: http://en.wikipedia.org/wiki/Computer_network
+[h]: http://www.tightvnc.com
+[i]: http://sourceforge.net/apps/mediawiki/tigervnc/index.php?title=Main_Page
+[j]: http://docs.microsoft.com/en-us/windows/wsl
+
+[1]: x-window-system.md
+[2]: #linuxmac-os-example-of-creating-a-tunnel
+[3]: #windows-example-of-creating-a-tunnel
+[4]: ../../../anselm/job-submission-and-execution.md
diff --git a/docs.it4i/general/accessing-the-clusters/graphical-user-interface/x-window-system.md b/docs.it4i/general/accessing-the-clusters/graphical-user-interface/x-window-system.md
index 1f87d62a5dfca725eab102db7c9cfbc0b5958866..1e2d5dcc77fb43ae36fac262ba5b39e0d9661f36 100644
--- a/docs.it4i/general/accessing-the-clusters/graphical-user-interface/x-window-system.md
+++ b/docs.it4i/general/accessing-the-clusters/graphical-user-interface/x-window-system.md
@@ -1,6 +1,6 @@
 # X Window System
 
-The X Window system is a principal way to get GUI access to the clusters. The **X Window System** (commonly known as **X11**, based on its current major version being 11, or shortened to simply **X**, and sometimes informally **X-Windows**) is a computer software system and network [protocol](http://en.wikipedia.org/wiki/Protocol_%28computing%29 "Protocol (computing)") that provides a basis for [graphical user interfaces](http://en.wikipedia.org/wiki/Graphical_user_interface "Graphical user interface") (GUIs) and rich input device capability for [networked computers](http://en.wikipedia.org/wiki/Computer_network "Computer network").
+The X Window system is a principal way to get GUI access to the clusters. The **X Window System** (commonly known as **X11**, based on its current major version being 11, or shortened to simply **X**, and sometimes informally **X-Windows**) is a computer software system and network [protocol][a] that provides a basis for [graphical user interfaces][b] (GUIs) and rich input device capability for [networked computers][c].
 
 !!! tip
     The X display forwarding must be activated and the X server running on client side
@@ -60,18 +60,17 @@ In order to display graphical user interface GUI of various software tools, you
 
 ### X Server on OS X
 
-Mac OS users need to install [XQuartz server](https://www.xquartz.org).
+Mac OS users need to install [XQuartz server][d].
 
 ### X Server on Windows
 
-There are variety of X servers available for Windows environment. The commercial Xwin32 is very stable and rich featured. The Cygwin environment provides fully featured open-source XWin X server. For simplicity, we recommend open-source X server by the [Xming project](http://sourceforge.net/projects/xming/). For stability and full features we recommend the
-[XWin](http://x.cygwin.com/) X server by Cygwin
+There are variety of X servers available for Windows environment. The commercial Xwin32 is very stable and rich featured. The Cygwin environment provides fully featured open-source XWin X server. For simplicity, we recommend open-source X server by the [Xming project][e]. For stability and full features we recommend the [XWin][f] X server by Cygwin
 
 | How to use Xwin | How to use Xming |
 |--- | --- |
-| [Install Cygwin](http://x.cygwin.com/) Find and execute XWin.exe to start the X server on Windows desktop computer.[If no able to forward X11 using PuTTY to CygwinX](#if-no-able-to-forward-x11-using-putty-to-cygwinx) | Use Xlaunch to configure the Xming. Run Xming to start the X server on Windows desktop computer. |
+| [Install Cygwin][g]. Find and execute XWin.exe to start the X server on Windows desktop computer.[If no able to forward X11 using PuTTY to CygwinX][1] | Use Xlaunch to configure the Xming. Run Xming to start the X server on Windows desktop computer. |
 
-Read more on [http://www.math.umn.edu/systems_guide/putty_xwin32.html](http://www.math.umn.edu/systems_guide/putty_xwin32.shtml)
+Read more [here][h].
 
 ## Running GUI Enabled Applications
 
@@ -116,7 +115,7 @@ The Gnome 2.28 GUI environment is available on the clusters. We recommend to use
 ### Gnome on Linux and OS X
 
 To run the remote Gnome session in a window on Linux/OS X computer, you need to install Xephyr. Ubuntu package is
-xserver-xephyr, on OS X it is part of [XQuartz](http://xquartz.macosforge.org/landing/). First, launch Xephyr on local machine:
+xserver-xephyr, on OS X it is part of [XQuartz][i]. First, launch Xephyr on local machine:
 
 ```console
 local $ Xephyr -ac -screen 1024x768 -br -reset -terminate :1 &
@@ -143,7 +142,7 @@ However this method does not seem to work with recent Linux distributions and yo
 
 Use XLaunch to start the Xming server or run the XWin.exe. Select the "One window" mode.
 
-Log in to the cluster, using [PuTTY](#putty-on-windows) or [Bash on Windows](#wsl-bash-on-windows). On the cluster, run the gnome-session command.
+Log in to the cluster, using [PuTTY][2] or [Bash on Windows][3]. On the cluster, run the gnome-session command.
 
 ```console
 $ gnome-session &
@@ -153,3 +152,16 @@ In this way, we run remote gnome session on the cluster, displaying it in the lo
 
 Use System-Log Out to close the gnome-session
 
+[1]: #if-no-able-to-forward-x11-using-putty-to-cygwinx
+[2]: #putty-on-windows
+[3]: #wsl-bash-on-windows
+
+[a]: http://en.wikipedia.org/wiki/Protocol_%28computing%29
+[b]: http://en.wikipedia.org/wiki/Graphical_user_interface
+[c]: http://en.wikipedia.org/wiki/Computer_network
+[d]: https://www.xquartz.org
+[e]: http://sourceforge.net/projects/xming/
+[f]: http://x.cygwin.com/
+[g]: http://x.cygwin.com/
+[h]: http://www.math.umn.edu/systems_guide/putty_xwin32.shtml
+[i]: http://xquartz.macosforge.org/landing/
diff --git a/docs.it4i/general/accessing-the-clusters/vpn-access.md b/docs.it4i/general/accessing-the-clusters/vpn-access.md
index 3275411fcc5d84ecdcf4f153908e3360ddffb0b2..518f2412cbf8abfddba2fa1b0156dc236d310d02 100644
--- a/docs.it4i/general/accessing-the-clusters/vpn-access.md
+++ b/docs.it4i/general/accessing-the-clusters/vpn-access.md
@@ -15,7 +15,7 @@ It is impossible to connect to VPN from other operating systems.
 
 ## VPN Client Installation
 
-You can install VPN client from web interface after successful login with [IT4I credentials](general/obtaining-login-credentials/obtaining-login-credentials/#login-credentials) on address [https://vpn.it4i.cz/user](https://vpn.it4i.cz/user)
+You can install VPN client from web interface after successful login with [IT4I credentials][1](general/obtaining-login-credentials/obtaining-login-credentials/#login-credentials) on address [https://vpn.it4i.cz/user][a](https://vpn.it4i.cz/user)
 
 ![](../../img/vpn_web_login.png)
 
@@ -43,7 +43,7 @@ After successful download of installation file, you have to execute this executa
 
 You can use graphical user interface or command line interface to run VPN client on all supported operating systems. We suggest using GUI.
 
-Before the first login to VPN, you have to fill URL **[https://vpn.it4i.cz/user](https://vpn.it4i.cz/user)** into the text field.
+Before the first login to VPN, you have to fill URL **[https://vpn.it4i.cz/user][a]** into the text field.
 
 ![](../../img/vpn_contacting_https_cluster.png)
 
@@ -72,3 +72,8 @@ After a successful logon, you can see a green circle with a tick mark on the loc
 ![](../../img/vpn_successfull_connection.png)
 
 For disconnecting, right-click on the AnyConnect client icon in the system tray and select **VPN Disconnect**.
+
+[1]: ../../general/obtaining-login-credentials/obtaining-login-credentials.md#login-credentials
+
+[a]: https://vpn.it4i.cz/user
+