RT Journal Article SR Electronic T1 Oas Models, Expected Returns, and a Steep Yield Curve JF The Journal of Portfolio Management FD Institutional Investor Journals SP 85 OP 93 DO 10.3905/jpm.1993.409456 VO 19 IS 4 A1 Clifford S Asness YR 1993 UL https://pm-research.com/content/19/4/85.abstract AB