← Search Econometrica Vol. 41 No. 5 1973 Concavity of Production Functions and Non-Increasing Returns to Scale James W. Friedman DOI10.2307/1913818 Volume41 Issue5 Pages981 Sources bibtex:phds-export.bib semanticscholar crossref openalex 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 ✓