Get extra 1.5GB Internal Storage on Galaxy S3 GT-I9300 with this hack!

Official Android 4.3 Update for Samsung Galaxy S3 GT-I9300 – I9300XXUGMK6

How to Downgrade Galaxy S3 GT-I9300 to Android 4.1.2 Jelly Bean [Back To Stock]

SuperNexus Gets Galaxy S3 GT-I9300 Users Android 4.4.2 KitKat Update, Latest Build KOT49H

Latest ClockworkMod (CWM) Recovery for International Galaxy S3 GT-I9300 (Android 4.4 Compatible!)

Samsung Galaxy S3 Philz Touch Advanced CWM Recovery: Downloads, Guides and Videos

Err.. Samsung planning a Galaxy S3 (GT-I9300) variant with Tizen OS? Not Android?

How to Update Galaxy S3 to Jelly Bean With MIUI ROM Based on Android 4.1

Install Android 4.1 Based ROM on Galaxy S3 — LiquidSmooth

Use Galaxy S3 Toolkit to Install ClockworkMod Recovery, Drivers, Root, Backup and Restore EFS and More