1. Waiting list candidates United Network for Organ Sharing http://www.unos.org/
2. Health Resources & Services Administration 2012 National survey of donation attitudes and behaviors http://organdonor.gov/dtcp/nationalsurveyorgandonation.pdf
3. U.S. and world population clock http://www.census.gov/popclock/
4. Organ Procurement and Transplantation Network National Data http://optn.transplant.hrsa.gov/latestData/viewDataReports.asp
5. Deaths: final data for 2008;Miniño;Natl Vital Stat Rep,2011