Salmon, Edward T., author
Routledge, 1995
Buku Teks
Boll, Heinrich, author
Bornheim : Lamuv, 1987
Buku Teks
Beare, William
Methuen & Co., 1964
Buku Teks
Philadelphia : Current History Inc.
Majalah, Jurnal, Buletin
Labour History, Economic History. Depart, The Univ.of Sydney
Majalah, Jurnal, Buletin