"Is the Rock Still Solid?", Time, October 19, 1970 City in the sky: the rise and fall of the World Trade Center, James Glanz, Eric Lipton.
בדיקה אחרונה ב-10 בנובמבר 2012.  "Is the Rock Still Solid?", Time, October 19, 1970 City in the sky: the rise and fall of the World Trade Center, James Glanz, Eric Lipton.