RT Journal Article SR Electronic T1 Market efficiency JF The Journal of Portfolio Management FD Institutional Investor Journals SP 28 OP 32 DO 10.3905/jpm.1985.409033 VO 12 IS 1 A1 Robert A. Haugen A1 Edgar Ortiz A1 Enrique Arjona YR 1985 UL https://pm-research.com/content/12/1/28.abstract AB