Hugul, Huray, Elif Cansel Gumus, and Zekayi Kutlubay. 2023. “Botulinum Toxin-A in the Treatment of Upper Facial Wrinkles: Efficacy Comparison of Different Formulations”. Annals of Medical Research 30 (10):1347-52. http://annalsmedres.org/index.php/aomr/article/view/4555.