On this date in 2010 Roy Halladay threw the 20th perfect game in

Remembering Roy Halladay's Perfect Game - Crossing Broad

This day in Phillies history: Roy Halladay spins masterful NLDS no-hitter

Roy Halladay career highlights: Cy Youngs and no-hitters

10 years later, Roy Halladay's perfect game lives on with Phillies, many others – The Morning Call

What a Week! Including Baseball's 24th Perfect Game!

Phillies' Roy Halladay throws perfect game in 1-0 victory over Marlins

Ten years later, Roy Halladay's perfect game lives on with the Phillies, Marlins, and so many others who were there

How many perfect games are there in MLB history? [Updated 2023]

10 Years Ago Today: Roy Halladay Throws a Perfect Game - Crossing Broad