RT Journal Article SR Electronic T1 Holding period is the key to risk thresholds JF The Journal of Portfolio Management FD Institutional Investor Journals SP 48 OP 54 DO 10.3905/jpm.1979.408681 VO 5 IS 2 A1 Francis H. Trainer, Jr. A1 Jess B. Yawitz A1 William J. Marshall YR 1979 UL https://pm-research.com/content/5/2/48.abstract AB