1. Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
2. Washington University School of Medicine, Department of Anesthesiology, Division of Pain Medicine, St. Louis, MO, USA
3. Mayo Medical Libraries, Mayo Clinic, Rochester, MN, USA
4. Department of Internal Medicine, Division of Preventive Medicine, Mayo Clinic, Rochester, MN, USA
5. Department of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA