PT - JOURNAL ARTICLE AU - Keith P. Ambachtsheer TI - The persistence of investment risk AID - 10.3905/jpm.1989.409240 DP - 1989 Oct 31 TA - The Journal of Portfolio Management PG - 69--71 VI - 16 IP - 1 4099 - https://pm-research.com/content/16/1/69.short 4100 - https://pm-research.com/content/16/1/69.full