@book{71671,
	author = {Black , John D and Mudgett, Bruce D.  and The Advisory Committee On Social 9 And Economic Research In Agriculture},
	title = {Research In Agricultural Index Numbers :},
	publisher = {Social Science Research Council,},
	year = {1938.},
	address = {New York :},
	url = {https://fll.law.cu.edu.eg/fulltext/bks/B13-07874.pdf}
}