Here's How Michael Phelps Trained for the 200m Butterfly
50m Freestyle World Record
Amazon.fr - Alexander Popov (swimmer): Swimming (sport), World record progression 50 metres freestyle, World record progression 100 metres freestyle, Swimming at the Summer Olympics - Miller, Frederic P., Vandome, Agnes F., McBrewster, John - Livres
Caeleb Dressel sets world record in 50-meter freestyle at ISL Grand Finale ahead of 2020 Tokyo Olympics - CBSSports.com
How Katie Ledecky became better at swimming than anyone is at anything - The Washington Post