Product name; small yellow flag, Size; the longest part is about 22cm, Material: satin step, Purpose: Referee props for rugby football games, Weight
Penalty Flag Football Challenge Flags Football Referee Flag for Party Accessory (Yellow and red)
NFL: Bijan Robinson scores 1st NFL touchdown in Atlanta Falcons' 24-10 win vs Carolina Panthers
NFL season: A glossary of terms and football jargon you'll need to fit in
What is the record for most NFL penalties in a game? - AS USA
From holding to head-butting: Here are the most and least common penalties in sports - ESPN
The Real Reason Why Football Referees Throw Yellow Penalty Flags
The Biggest Upsets in Recent Rugby History and the Data Behind Them
Pass Interference or Not? No One in the N.F.L. Seems to Know - The New York Times
Players call foul over NFL's emphasis on taunting rules - The Boston Globe
The NFL Offenses That Get The Most Out Of Defensive Pass Interference
Seeing Yellow: The Data Behind Penalties in the NFL
Seeing yellow: The data behind penalties in the NFL - Main Street Media of Tennessee
Targeting: The history, the current backlash and the future, Tiger Kickoff