Columbia Accident Investigation Board (2003). "CAIB page 153 (PDF)"(PDF). Archived from the original(PDF) on May 16, 2011. Retrieved December 17, 2010. {{cite web}}: Cite has empty unknown parameter: |1= (help)
Columbia Accident Investigation Board (2003). "CAIB page 153 (PDF)"(PDF). Archived from the original(PDF) on May 16, 2011. Retrieved December 17, 2010. {{cite web}}: Cite has empty unknown parameter: |1= (help)