RT Journal Article SR Electronic T1 Can Selectivity Pay in an Efficient Market? JF The Journal of Portfolio Management FD Institutional Investor Journals SP 19 OP 22 DO 10.3905/jpm.1976.408573 VO 2 IS 4 A1 Keith P. Ambachtsheer YR 1976 UL https://pm-research.com/content/2/4/19.abstract AB