Page One Publishing Ple Ltd, 2012
Buku Referensi
Watson, Donald ; Plattus, Alan ; Shibley, Robert G., editor
McGraw - Hill, 2003
Buku Referensi
Graaf, Reinier de, 1964-, author
Harvard University Press, 2017
Buku Teks
Weaver, Robert C.
Buku Teks
Linton, Harold, author
McGraw-Hill, 1999
Buku Teks