APA (7th ed.) Citation

Singer, H. W. (1949). Economic progress in underdeveloped countries. Social Research, 16, 1.

Chicago Style (17th ed.) Citation

Singer, H. W. "Economic Progress in Underdeveloped Countries." Social Research 16 (1949): 1.

MLA (9th ed.) Citation

Singer, H. W. "Economic Progress in Underdeveloped Countries." Social Research, vol. 16, 1949, p. 1.