RT Journal Article SR Electronic T1 After 50 years, nothing new nor likely JF The Journal of Portfolio Management FD Institutional Investor Journals SP 26 OP 35 DO 10.3905/jpm.1979.408706 VO 6 IS 1 A1 Arthur Zeikel YR 1979 UL https://pm-research.com/content/6/1/26.abstract AB