No person shall purchase or contract for spring water, ice, waxing, rug shampooing, draperies, towels, cleaning, glass washing, furniture polishing, lamp servicing, cleaning or electric fixtures, removal of waste paper, rubbish and garbage, or other like services at the World Trade Center except from contractors, companies or persons approved by the Port Authority.
N.Y. Comp. Codes R. & Regs. Tit. 21 § 1290.17