Gruber, Ruth
Puerto Rico : island of promise
Hill and Wang, 1960
 Buku Teks SO
Gruber, Ruth
Puerto Rico: island of promise
Hill and Wang, 1960
 Buku Teks SO
Friedrich, Carl J.
Puerto Rico : middle road to freedom
Rinehart, 1959
 Buku Teks SO
Hanson, Earl Parker
Transformation : the story of modern Puerto Rico
Simon and Shuster, 1955
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Wells, Henry
The modernization of Puerto Rico: apolitical study of changing values and institutions
Harvard University Press, 1969
 Buku Teks SO