Smartphone dependence, addiction, and insomnia among medical students during the COVID-19 pandemic - Virgilio E. Failoc-Rojas; Alicia Torres-Mera; Darwin A. León-Figueroa; David Lira; Flor M. Santander-Hernández; Miguel A. Guevara-Morales; Cristian Díaz-Vélez; Mario J. Valladares-Garrido (PLoS ONE)