RT Journal Article SR Electronic T1 Equity Research After Modern Portfolio Theory JF The Journal of Portfolio Management FD Institutional Investor Journals SP 52 OP 56 DO 10.3905/jpm.1979.408684 VO 5 IS 3 A1 Stephen B. Timbers YR 1979 UL https://pm-research.com/content/5/3/52.abstract AB