What happened to Damar Hamlin?
Bills safety Damar Hamlin returns to action in first regular-season game since cardiac arrest, Sports
What is commotio cordis, which NFL player Damar Hamlin says stopped his heart?
Bills' safety ready to return to action
Back to work not business as usual for Damar Hamlin's peers – WABE
Bills safety Damar Hamlin returns to action in first regular-season game since cardiac arrest
Damar Hamlin Remains in Critical Condition as NFL Says Game Will Not Resume This Week - WSJ
Bills' Damar Hamlin plays in first game since cardiac arrest
Bills safety Damar Hamlin makes return to Highmark Stadium
When Damar Hamlin collapsed, the NFL deployed its emergency action plan - The Washington Post