Gujarati, Damodar N., author
McGraw-Hill, 1984
Buku Teks
Hall, Ford P.
McGraw-Hill Book Company,Inc., 1949
Buku Teks
Dimock, Marshall Edward, author
Henry Holt, 1953
Buku Teks
Watson, Donald Stevenson, author
Houghton Miffiln, 1960
Buku Teks
Dersal, William R. Van
Harper & Brother, 1962
Buku Teks