Link

Einstein, H.H., Azzouz, A.S., McKown, A.F., and Thompson, D.E. (1983). Evaluation of design and performance – Porter Square transit station chamber lining. In: Proceedings of the Rapid Excavation and Tunneling Conference, Chicago, Illinois, 12-16 June 1983. New York: Society of Mining Engineers of the American Institute of Mining, Metallurgical, and Petroleum Engineers, 1983. OneMine.org library