1. Division of Otolaryngology-Head and Neck Surgery, Department of Surgery; University of Calgary; Calgary Alberta Canada
2. the Division of Rhinology and Sinus Surgery, Oregon Sinus Center, Department of Otolaryngology-Head and Neck Surgery; Oregon Health and Science University; Portland Oregon
3. the Division of Rhinology and Sinus Surgery, Department of Otolaryngology-Head and Neck Surgery; Medical University of South Carolina; Charleston South Carolina
4. Department of Otolaryngology-Head and Neck Surgery; Stanford School of Medicine; Stanford California U.S.A