diff --git a/README.md b/README.md
index 303f171..6312f51 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,7 @@ Setup instructions for Ubuntu on IMACs
 ## 2011 IMAC
 
 ### Disable startup chime
+https://wiki.archlinux.org/title/mac#Mute_startup_chime
 
 The startup chime volume is controlled by the EFI variable SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82. So it can be muted with
 
@@ -20,6 +21,7 @@ chattr -i /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe
 After that, run the printf command and it should overwrite the file properly. Verify the file's contents and then set the immutable bit again with chattr +i once satisfied. 
 
 ### Fix screen brightness adjust
+https://askubuntu.com/a/1478635
 
 Edit /etc/default/grub and modify the GRUB command line to include the following
 ```
@@ -31,7 +33,8 @@ Rebuild GRUB menu afterwards
 update-grub
 ```
 
-### Install mbp fan controll
+### Install mbp fan control
+https://askubuntu.com/a/1323838
 
 ```
 apt install mbpfan