RT Journal Article SR Electronic T1 Risk, diversification, and the investment horizon JF The Journal of Portfolio Management FD Institutional Investor Journals SP 41 OP 47 DO 10.3905/jpm.1991.409334 VO 17 IS 3 A1 Kirt C. Butler A1 Dale L. Domian YR 1991 UL https://pm-research.com/content/17/3/41.abstract AB