RT Journal Article SR Electronic T1 Making sense out of unstable alphas and betas JF The Journal of Portfolio Management FD Institutional Investor Journals SP 19 OP 22 DO 10.3905/jpm.1985.408995 VO 11 IS 2 A1 Bill McDonald YR 1985 UL https://pm-research.com/content/11/2/19.abstract AB