RT Journal Article SR Electronic T1 Estimation risk and optimal portfolios JF The Journal of Portfolio Management FD Institutional Investor Journals SP 40 OP 43 DO 10.3905/jpm.1985.409030 VO 12 IS 1 A1 Robert A. Pari A1 Son-Nan Chen YR 1985 UL https://pm-research.com/content/12/1/40.abstract AB