PT - JOURNAL ARTICLE AU - Peter L. Bernstein TI - The concealed factors AID - 10.3905/jpm.1980.408753 DP - 1980 Apr 30 TA - The Journal of Portfolio Management PG - 4 VI - 6 IP - 3 4099 - https://pm-research.com/content/6/3/4.short 4100 - https://pm-research.com/content/6/3/4.full