Costa, D. L. (1998). The wage and the length of the work day: From 1890s to 1991. National Bureau of Economic Research.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रCosta, Dora L. The Wage and the Length of the Work Day: From 1890s to 1991. Cambridge: National Bureau of Economic Research, 1998.
एमएलए (9वां संस्करण) प्रशस्ति पत्रCosta, Dora L. The Wage and the Length of the Work Day: From 1890s to 1991. National Bureau of Economic Research, 1998.
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