Hicks, John R., author
Clarendon Press, 1959
Buku Teks
Theil, Henri, author
North-Holland, 1975
Buku Teks
Henderson, Hubert, author
Nisbet, 1954
Buku Teks
Schultz, Henry
The Univ. of Chicago Press , 1938
Buku Teks
Clarckson, Geoffrey
Prentice-Hall, 1962
Buku Teks