@inbook{3504552,
author={Andrew T. Gray, MD, PhD},
editor={Hadzic, Admir},
title={Chapter 50. Introduction to Ultrasound-Assisted Regional Anesthesia Techniques},
booktitle={NYSORA Textbook of Regional Anesthesia and Acute Pain Management},
publisher={The McGraw-Hill Companies},
address={New York, NY},
year={2007},
url={accessanesthesiology.mhmedical.com/content.aspx?aid=3504552}
}