301.35 Sor Sorokin, Pitirim Alexandrovich, 1889-- P Principles of rural--urban sociology by Pitirim Sorokin and Carle C. Zimmerman. New York, H. Holt [1931, c1929] xv, 652 p. tablas 22cm ( American social science series) Notas bibliograficas al pie de las paginas