Federal Bureau of Investigation (2008-02-04). "Hijackers' Timeline"(PDF). NEFA Foundation. s. 288. Arkiveret fra originalen(PDF) 12. oktober 2008. Hentet 2008-10-06.
Federal Bureau of Investigation (2008-02-04). "Hijackers' Timeline"(PDF). NEFA Foundation. s. 288. Arkiveret fra originalen(PDF) 12. oktober 2008. Hentet 2008-10-06.