Glorier Incorporated, 1993
Buku Referensi
Kassirsky, I., author
Peace Publisher, [Date of publication not identified]
Buku Referensi
Briggs, John C., author
McGraw-Hill, 1974
Buku Teks
[publisher not identified], [date of publication not identified]
Naskah
Kern, R.A., author
[publisher not identified], [date of publication not identified]
Buku Klasik