Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Concussion:

This text has been unreferenced on Wikipedia for a very long time. If you can't find a source, be bold and remove it!

"

In the past, the decision to allow athletes to return to participation was frequently based on the grade of concussion.[1] However, current research and recommendations by professional organizations including the National Athletic Trainers' Association recommend against such use of these grading systems.[citation needed] Currently, injured athletes are prohibited from returning to play before they are symptom-free during both rest and exertion and until results of the neuropsychological tests have returned to pre-injury levels.[2] Three grading systems have been most widely followed: by Robert Cantu, the Colorado Medical Society, and the American Academy of Neurology.[3] Each employs three grades, as summarized in the following table:[4]