RT Journal Article SR Electronic T1 Bull Market? Bear Market? JF The Journal of Portfolio Management FD Institutional Investor Journals SP 26 OP 29 DO 10.3905/jpm.1997.26 VO 24 IS 1 A1 Robert D. Arnott A1 Peter L. Bernstein YR 1997 UL https://pm-research.com/content/24/1/26.abstract AB