Graphic. Figure 1-3 WTC impact locations and resulting fireballs. Sept 11, 2001.
FEMA - Therese McAllister. Therese McAllister. Jonathan Barnett. John Gross. Ronald Hamburger,  Jon Magnuson
<a rel="nofollow" class="external free" href="http://www.fema.gov/pdf/library/fema403_ch1.pdf">http://www.fema.gov/pdf/library/fema403_ch1.pdf</a> (pag 5)