RT Journal Article SR Electronic T1 Can portfolio managers outrun the random walkers? JF The Journal of Portfolio Management FD Institutional Investor Journals SP 32 OP 36 DO 10.3905/jpm.1974.408498 VO 1 IS 1 A1 Black, Fischer YR 1974 UL http://jpm.pm-research.com/content/1/1/32.abstract AB