(EN) Staff statement no. 4 - «The four flights» (PDF), su 9-11commission.gov., National Commission on Terrorist Attacks Upon the United States, 27 gennaio 2004, pag. 2 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pag. 7 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, luglio 2004, Note del cap. 1, pag. 452 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pag. 21 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pagg. 7-8 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pagg. 21-22 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pag. 8 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pag. 22 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pag. 23 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pag. 24 (.pdf file).
(EN) The 9/11 Commission Report (PDF), su govinfo.library.unt.edu., National Commission on Terrorist Attacks Upon the United States, 22 luglio 2004, cap. 1, pag. 2 (.pdf file).
(EN) United Airlines Worldwide Timetable, su uatimetable.com (archiviato dall'url originale il 30 settembre 2007)., United Airlines, 2008, pag. 18 (.pdf file).