RT Journal Article SR Electronic T1 Paradox in the current crisis in efficient market theory JF The Journal of Portfolio Management FD Institutional Investor Journals SP 30 OP 34 DO 10.3905/jpm.1991.409326 VO 17 IS 2 A1 Simon M. Keane YR 1991 UL https://pm-research.com/content/17/2/30.abstract AB