4-time champion, All-Pro tight end Rob Gronkowski announces
Rob Gronkowski retires from the NFL again - The Boston Globe
Rob Gronkowski Retiring From Tampa Bay Bucs, NFL For 2nd Time
NFL legend Rob Gronkowski, 33, retires for second time - BBC Sport
Rob Gronkowski on retiring from NFL at age 29: 'I didn't even want
Rob Gronkowski retirement: How the future HOF tight end's decision
Rob Gronkowski retires from the NFL
NFL world reacts to Rob Gronkowski retiring for a second time
Rob Gronkowski announces he's retiring from the NFL for the second
Rob Gronkowski retiring from the NFL again
Rob Gronkowski retires after 11 seasons, 4 Super Bowl championships