Teichert, Pedro C.M., author
Bureau of Business Research Mississippi University , 1959
Buku Teks
Foxley, Alejandro
University of California Press , 1983
Buku Teks
The John Hopkins University Press, 1995
Buku Teks
Southern Methoddist University Press, 1962
Buku Teks
Clagett, Helen L.
Oceana Publications, 1952
Buku Teks