1. Treatment of glabellar frown lines with C. botulinum-A exotoxin;Carruthers;J Dermatol Surg Oncol,1992
2. FDA https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2002/botuall041202L.htm
3. FDA www.fda.gov/News_Events/Newsroom/PressAnnouncements/ucm367662.htm
4. BOTOX® Cosmetic (onabotulinumtoxinA) for injection, for intramuscular use Irvine, CA Allergan 2016
5. DYSPORT® for injection (abobotulinumtoxinA) Slough, UK Ipsen, Galderma 2012