RT Journal Article SR Electronic T1 How Much Diversification is Desirable? JF The Journal of Portfolio Management FD Institutional Investor Journals SP 42 OP 44 DO 10.3905/jpm.1980.42 VO 7 IS 1 A1 Harold Bierman, Jr. YR 1980 UL https://pm-research.com/content/7/1/42.abstract AB