1. Agency for Healthcare Research and Quality 2011a Cost-to-charge ratio files: 2009 Kids' Inpatient Database (KID) user guide http://www.hcup-us.ahrq.gov/db/state/CCR2009KIDUserGuide.pdf
2. Agency for Healthcare Research and Quality 2011b HCUP Kids' Inpatient Database (KID). Healthcare Cost and Utilization Project (HCUP). 2009 http://www.hcup-us.ahrq.gov/kidoverview.jsp
3. Agency for Healthcare Research and Quality 2011c Introduction to the HCUP KIDS' Inpatient Database (KID) 2009 http://www.hcup-us.ahrq.gov/db/nation/kid/KID_2009_Introduction.pdf
4. Agency for Healthcare Research and Quality 2014 HCUP procedure classes https://www.hcup-us.ahrq.gov/toolssoftware/procedure/procedure.jsp
5. Racial variation in the quality of surgical care for prostate cancer;Barocas;J Urol,2012