1. A. Malcolm Drilling Co. (2011). "Sound transit U230 Capitol Hill Station" Company Brochure January.
2. Crockford R.; Lizzo J; and Wise J. (2008). "Underpinning the Existing No. 1 Subway Line at the World Trade Center" DFI 33rd Annual and 11th International Conference on Piling and Deep Foundations NY NY October.
3. Frappin P. and Vernhes J.D. (2005). "CYLJET® an Innovative Method for Jet Grouting Column Diameter Measurement" Technical Paper furnished by Nicholson Construction Company Proceedings of the 6th International Conference on Ground Improvement Techniques Coimbra Portugal July.