Zelinsky, Marilyn
McGraw-Hill, 1997
Buku Teks
Garg, Shalini, author
Emerald Publishing Limited, 2020
eBooks
Ottensmeyer, Edward J., author
McGraw-Hill, 1996
Buku Teks
Kierkegaard, Soren, 1813-1855, author
Liveright Publishing Corporation, 2014
Buku Teks
Earle, Liz, author
Boxtree , 1995
Buku Teks