Blalock, H. (1964) Causal Inference in Non-Experimental Research. Chapel Hill: Univ. of North Carolina Press .
2.
Cnudde, C. and D. McCrone (1967) "Toward a communication theory of democratic political development: a causal model." Amer. PoL Sci. Rev.61 (January): 72-80.
3.
Cutright, P. (1963) "National political development: measurement and analysis." Amer. Soc. Rev.28 (April): 253-264.
4.
Gibbs, J. (1966) "Measures of urbanization." Social Forces45 (March): 170-177.
5.
Kelley, T.L. (1.947), pp. 363-365 in Fundamentals of Statistics. Cambridge, Mass.: Harvard Univ. Press.
6.
Lerner, D.L. (1957) "Communications systems and social systems: a statistical exploration in history and policy." Behavioral Science2 (March): 266-275.
7.
Pye, L.W. (1966) Aspects of Political Development. Boston: Little, Brown.
8.
Scaff, R. (1955) The Philippines Answer to Communism. Stanford, Calif.: Stanford Univ. Press.
9.
Smith, R. (1958) Philippine Freedom 1946-1958. New York: Columbia Univ. Press.
10.
Starner, F.L. (1961) Magsaysay and the Philippine Peasantry: The Agrarian Impact on Philippine Politics 1953-1956. Los Angeles: Univ. of California Press.