Effects of the OnabotulinumtoxinA follow-up delay in migraine course during the COVID-19 lockdown - Gonzalez-Martinez, A; Planchuelo-Gómez, Á; Guerrero, ÁL; García-Azorín, D; Santos-Lasaosa, S; Navarro-Pérez, MP (Neurol Sci, 2021)