Stephen P. Norris
Sense, 2012
eBooks
Heater, Derek, author
Longman, 1990
Buku Teks
edited by Matthew Carlin and Jason Wallin
Bloomsbury Academic, 2014
Buku Teks
Ben-Chai, David, author
Sense, 2012
eBooks
Bergamini, David, author
Time Incorporated, 1963
Buku Referensi