RT Journal Article SR Electronic T1 Putting Markowitz theory to work JF The Journal of Portfolio Management FD Institutional Investor Journals SP 70 OP 74 DO 10.3905/jpm.1981.408816 VO 7 IS 4 A1 J. D. Jobson A1 Robert M Korkie YR 1981 UL https://pm-research.com/content/7/4/70.abstract AB