← Search Econometrica Vol. 17 No. 2 1949 A System of Equations Explaining the United States Trade Cycle, 1921 to 1941 Colin Clark DOI10.2307/1905688 Volume17 Issue2 Pages93 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 ✓