RT Journal Article SR Electronic T1 “Sideways Betas” JF The Journal of Portfolio Management FD Institutional Investor Journals SP 67 OP 68 DO 10.3905/jpm.1976.408576 VO 2 IS 4 A1 William F. Sharpe A1 Allan Silver YR 1976 UL https://pm-research.com/content/2/4/67.abstract AB