Smaug vs Drogon - Fight to the death

What is the most accurate size estimation for Glaurung the dragon? - Quora

Calculating the size of Glaurung : r/tolkienfans

Dragons of Middle Earth vs Elder Dragons & Souls Dragons

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

Middle Earth Villains Size Comparison--Orcs to Ancalagon

The One Ring :: View topic - Glaurung the Golden

Lord of the Rings' Biggest Dragon Was Ancalagon, Not Smaug

Acnologia vs Ancalagon and Glaurung - Battles - Comic Vine

New mud dragons from Svalbard: three new species of Cristaphyes and the first Arctic species of Pycnophyes (Kinorhyncha: Allomalorhagida: Pycnophyidae) [PeerJ]