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MacDonald & Evans, 1975
Buku Teks
Arya, Jagdish C., author
Prentice-Hall, 1981
Buku Teks
Pusat Kajian Ilmu Ekonomi (Puskanomi) Universitas Indraprasta PGRI, 2016
Majalah, Jurnal, Buletin
Brown, E.H. Phelps, author
Sir Isaac Pitman & Sons, 1953
Buku Teks
Mills, Richard L., author
McGraw-Hill Kogakusha, 1977
Buku Teks