1 in 3 former NFL players believe they have CTE, according to a new Harvard study The Philadelphia InquirerA third of former NFL players surveyed believe they have CTE, researchers find NPROne-Third of Former Football Players Believe They Have Degenerative Brain Disease CTE, New Report Finds PEOPLEStudy of former NFL players finds 1 in 3 believe they have chronic traumatic encephalopathy Medical XpressWhat are the early warning signs of CTE? New clues emerge National Geographic