Palmer, Donald, author
McGraw-Hill, 2013
Buku Teks
Palmer, Donald, author
McGraw-Hill, 2001
Buku Teks
edited by Dagobert D. Runes
Littlefield, Adams & Co., 1959
Buku Referensi
Baggini, Julian, author
Palgrave Macmillan, 2012
Buku Teks
edited by Nicholas Bunnin and E. P. Tsui-James
Wiley, 2003
Buku Teks