Zweifel, Thomas D.
Communicate or die : Getting results through speaking and listening
Selectbooks, 2009
 Buku Teks
Woolley, Leonard
A Forgotten kingdom / Leonard Woolley
Penguin Books , 1953
 Buku Teks
Schnitger, F.M.
Forgotten kingdoms in Sumatra / by F.M. Schnitger
E.J. Brill, 1964
 Buku Teks
Mossner, Ernest Campbell
The forgotten hume : le bon David
Columbia University Press, 1943
 Buku Teks
Schnitger, F.M.
Forgotten kingdoms in Sumatra / by F. M. Schnitger
Oxford University Press, 1989
 Buku Teks