Doctor Who' Christmas countdown Day 2: 'The Christmas Invasion'
Doctor Who: The episodes from Christmas past - CBBC Newsround
An absolutely not definitive ranking of 'Doctor Who' Christmas specials
On This Day… In 2009 'The End of Time' Began - Blogtor Who
Doctor Who: The Next Doctor, 2008 Christmas Special [DVD]: Amazon.co.uk: David Tennant, David Morrissey, Dervla Kirwan, Velile Tshabalala, David Tennant, David Morrissey, Russell T Davies: DVD & Blu-ray
Doctor Who: The episodes from Christmas past - CBBC Newsround
Doctor Who" The Christmas Invasion (TV Episode 2005) - IMDb