Johns, Roe L.
Prentice-Hall, 1975
Buku Teks
Johns, Roe L.,
Prentice-Hall, 1975
Buku Teks
Merwin, Charles L.
National Bureau of Economic Research, Inc., 1942
Buku Teks
Grambs, Jean D.
Holt, Rinehart and Winston, 1964
Buku Teks
Stegmen, Michael A.
MIT Press , 1970
Buku Teks