Phillips, P. C. B., Shi, S., & Yu, J. (2015a). Testing for
multiple bubbles: Historical episodes of exuberance and collapse in the S&P
500. International Economic Review, 56(4), 1034--1078.
Phillips, P. C. B., Shi, S., & Yu, J. (2015b). Testing for
multiple bubbles: Limit Theory for Real-Time Detectors. International
Economic Review, 56(4), 1079--1134.