O’Brien, Tanya, and Aileen Lynch. “The Impact of the COVID-19 Lockdown Restrictions on Physical Activity Levels in European Adolescents: A Systematic Review and Meta-Analysis”. European Scientific Journal, ESJ 15 (March 14, 2023): 252. Accessed May 30, 2026. https://last.eujournal.org/index.php/esj/article/view/16530.