Georges, Walter
Quorum Books , 1987
Buku Teks
Oxenfeldt, Alfred Richard
Prentice-Hall, 1951
Buku Teks
North-Holland, 1976
Buku Teks
National Bureau of Economic Research, 1943
Buku Teks
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 1985
UI - Skripsi (Membership)