The sizes of the Dragon's we've - The Targaryen Supremacy

Glaurung, The One Wiki to Rule Them All

Your Quick Guide To Dragons in Middle-earth (and how to tackle one) – A Tolkienist's Perspective

Glaurung by YellowPanda2001 on DeviantArt

NO SPOILERS] Westeros's Drogon(short necked, younger and faithful) vs Middle Earth's Smaug(Long necked, badass, intelligent, without a master). Who would win? Personally, I prefer short necked dragons but Smaug might can easily

Ancalagon the Black makes Smaug look like a little baby which just emerged from egg. - 9GAG

Dragon scale: Why it's impossible to size up Tolkien's Middle-earth

The One Ring :: View topic - Glaurung the Golden

The Complete Size Guide of the Creatures of Middle-Earth

Biggest dragon in popular-culture? - Page 3

David Grigoryan - Silmarillion. Illustrations