RT Journal Article SR Electronic T1 Are Benchmark Portfolios Efficient? JF The Journal of Portfolio Management FD Institutional Investor Journals SP 34 OP 40 DO 10.3905/jpm.1992.34 VO 19 IS 1 A1 Richard C. Grinold YR 1992 UL https://pm-research.com/content/19/1/34.abstract AB