1. Society of Thoracic Surgeons [Internet]. Chicago: The Society; c2010 [updated 2009 Jan 12; cited 2009 Feb 19]. The Society of Thoracic Surgeons STS National Database and Outcomes Program Participation Manual [14 pp]. Available from: http://www.sts.org/documents/pdf/ndb/Database_Manual_2009.pdf
2. The Society of Thoracic Surgeons [Internet]. Chicago: The Society; c2010 [cited 2009 Feb 17]. The Society of Thoracic Surgeons, Database Manager Section [about 1 index screen]. Available from: http://www.sts.org/sections/stsnationaldatabase/datamanagers/
3. The Society of Thoracic Surgeons [Internet]. Chicago: The Society; c2010 [updated 2006 Oct 27; cited 2009 Feb 17]. STS Adult Cardiac Database Training Manual, version 2.52 [about 1 index screen]. Available from: http://www.sts.org/sections/stsnationaldatabase/datamanagers/adultcardiacdb/datacollection/articles/article1.html
4. Verification of data in congenital cardiac surgery;Clarke;Cardiol Young,2008
5. Measuring nominal scale agreement among many raters;Fleiss;Psychol Bull,1971