← Search Journal of Finance Vol. 36 No. 3 1981 Portfolio Theory, 25 Years After. Jonathan Ingersoll; E. J. Elton; Martin J. Gruber DOI10.2307/2327537 Volume36 Issue3 Pages753 Sources semanticscholar openalex crossref Cite APA 7 MLA 9 Chicago (author–date) Harvard Elsevier Harvard (JFE, JBF…) The Accounting Review Academy of Management American Marketing Association INFORMS (Management Science) Copy citation Copied ✓