What happens in the brain to make us 'catch' yawns - BBC News
Yawning - The surprising details behind a yawn | HuffPost Contributor
Is it Normal to Yawn Excessively? | WR Mattress
4 Things Your Yawns Are Trying To Tell You | Prevention
A simple slice of science - Why do we yawn? - Dr. How's Science Wows
Yawning: Causes and reasons for contagious yawning
Why Do We Yawn & Is It Contagious? | How To Sleep
What is it about yawning?
Why Do We Yawn When We're Sleepy? Everything You Should Know
What Is A Yawn? - YouTube
Yawning: An unsolved mystery
Why we yawn and What it means
Open wide: why yawning reveals much about your level of empathy | Life and style | The Guardian
Why do we yawn and is it really contagious? | NationalWorld
Why Do We Yawn? - YouTube
Yawn - Wikipedia
Why do we yawn? | Library of Congress
Why is yawning contagious? Your tired tick, explained.
What is it about yawning?
What Is Yawning? | SiOWfa15: Science in Our World: Certainty and Controversy
Why do we yawn? Scientists are still searching for the answer
The Word That Makes 55% of People Yawn When They Read It | Reader's Digest
Yawns Are Cool · Frontiers for Young Minds
If sex is a yawn, you may actually be turned on
