Bart Streumer.
Wiley-Blackwell , 2014
Buku Teks
Kagan, Shelly, author
Westview Press, 1997
Buku Teks
MacIntyre, Alasdair, author
Rontledge , 1998
Buku Teks
Ian E. Thompson [and others]
Elsevier, 2006
Buku Teks
Albert, Ethel M., author
American Book Company, 1953
Buku Teks