The 12 Biggest Nerfs in "Hearthstone" History - LevelSkip
Undertaker nerf bypassed if you don't restart client (you can currently climb ranked with him pre-nerf) - General Discussion - Hearthstone General - HearthPwn Forums - HearthPwn
History of the Hunter #1: Unleash the Nerfs! — Team Metaminds
Undertaker Nerf - Hearthstone Patches - Out of Cards
Hearthstone's powerful Undertaker minion card to be | GameWatcher