RT Journal Article SR Electronic T1 Evidence of superior performance from timing JF The Journal of Portfolio Management FD Institutional Investor Journals SP 38 OP 42 DO 10.3905/jpm.1989.409205 VO 15 IS 3 A1 Robert F. Vandell A1 Jerry L. Stevens YR 1989 UL https://pm-research.com/content/15/3/38.abstract AB