RT Journal Article SR Electronic T1 The Effect of Errors in Means, Variances, and Covariances on Optimal Portfolio Choice JF The Journal of Portfolio Management FD Institutional Investor Journals SP 6 OP 11 DO 10.3905/jpm.1993.409440 VO 19 IS 2 A1 Vijay Kumar. Chopra A1 William T. Ziemba YR 1993 UL https://pm-research.com/content/19/2/6.abstract AB