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.
Parsley (Edwards) TL. Review of the phantom respondents: opinion surveys and political representation. J Off Stat. 1994;10(3):351-5.