Michael Norman puts world record on notice at Mt. SAC relays – Orange County Register
Sydney McLaughlin breaks women's 400m world record in front of home crowd | Sports | dailyemerald.com
Karsten Warholm Sets World Record in 400-Meter Hurdles - The New York Times
Dalilah Muhammad Breaks Her Own World Record in the 400-Meter Hurdles - The New York Times
Usain Bolt record collection: the sprint king's greatest hits
Mighty McLaughlin shatters 400 metres hurdles world record | Reuters
400 metres at the Olympics - Wikipedia
Miller-Uibo still leads world list in 200, 400 metres | The Tribune
Sydney McLaughlin breaks women's 400 metres hurdles world record ahead of Tokyo Olympics - ABC News
200 metres - Wikipedia
Norway's Warholm breaks 400 metres hurdles world record | Reuters
400 Metres
Track's Most Resilient (and Suspect) Record Is in Danger - The New York Times
The 400 Meter WORLD RECORD || WAYDE VAN NIEKERK'S Plan for 2021 - YouTube
Karsten Warholm breaks men's 400 hurdles world record in Norway
Van Niekerk betters 400m world record
Usain Bolt - Wikipedia
400 metres hurdles - Wikipedia
400 metres - Wikipedia
Wayde van Niekerk: South African smashes 400-meter world record to take gold | CNN
Has a decathlon athlete ever broken a world record in a specific item? - Quora
400 Metres Hurdles
Brilliant Van Niekerk smashes 400m world record | Reuters
