A prospective, randomized, parallel group study analyzing the effect of BTX-A (Botox) and Nonanimal Sourced Hyaluronic Acid (NASHA, Restylane) in Combination Compared with NASHA (Restylane) Alone in Severe Glabellar Rhytides in Adult Female Subjects: Treatment of Severe Glabellar Rhytides with a Hyaluronic Acid Derivative Compared with the Derivative and BTX-A - Carruthers,J.; Carruthers,A. (Dermatol Surg, 2003)