RT Journal Article SR Electronic T1 Investment Horizons and Performance Measurement JF The Journal of Portfolio Management FD Institutional Investor Journals SP 18 OP 22 DO 10.3905/jpm.1978.408627 VO 4 IS 2 A1 Seymour Smidt YR 1978 UL https://pm-research.com/content/4/2/18.abstract AB