Lopez-Vicente M, Forns J, Esnaola M, Suades-Gonzalez E, Alvarez-Pedrerol M, Robinson O, Julvez J, Garcia-Aymerich J, Sunye J. Physical activity and cognitive trajectories in schoolchildren. Pediatr Exerc Sci. 2016 Aug;91(8):770-5.
Johannes CB, Le TK, Zhou X, Johnston JA, Dworkin RH. The prevalence of chronic pain in United States adults: results of an internet-based survey. J Pain. 2010 Nov 1;11(11):1230-9.