De Boulle, Koen, Philip Werschler, Michael H Gold, Gerhard Sattler, Patricia Ogilvie, Cheri Mao, Domenico Vitarella, Xiaofang Lei, and Bhushan Hardas. 2017. “Efficacy and Safety of OnabotulinumtoxinA for Moderate-to-Severe Forehead Lines in Subjects With Upper Facial Lines”. SKIN The Journal of Cutaneous Medicine 1 (3.1):s73. https://doi.org/10.25251/skin.1.supp.72.