Author,Title,Edition,Publisher,Year,Series,Number,ISBN,ISSN,URL
"Barger, Harold M. and Landsberg, Hans H.","American agriculture, 1899-1939 : a study of output, employment and productivity",,National Bureau of Economic Research,1942,"Publications of the National Bureau of Economic Research, Incorporated",,,,https://cir.nii.ac.jp/crid/1130282271391008256