Geographic Differentials of Agricultural Wages in the United States H. Gollnick; Willis D. Weatherford Econometrica 1959 27(1), 131
Consumer Demand in the United States, 1929-1970. Analyses and Projections H. Gollnick; H. S. Houthakker; Lester D. Taylor Econometrica 1968 36(1), 203