HNTB Corporation; Parsons Brinckerhoff Quade & Douglas, Inc.; Fitzgerald & Halliday, Inc.; KKO & Associates. "I-93 Corridor Multi-Modal Transit Investment Study"(PDF). New Hampshire Department of Transportation. p. 7. Archived(PDF) from the original on September 9, 2015. Retrieved December 2, 2015.
HNTB Corporation; Parsons Brinckerhoff Quade & Douglas, Inc.; Fitzgerald & Halliday, Inc.; KKO & Associates. "I-93 Corridor Multi-Modal Transit Investment Study"(PDF). New Hampshire Department of Transportation. p. 7. Archived(PDF) from the original on September 9, 2015. Retrieved December 2, 2015.