Robertson, Brian J.
Henry Holt and Company, 2015
Buku Teks
Russel, Bertrand
Zheng Zhong Shu Ju, 1987
Buku Teks
Miklos Kengyel
Springer, 2012
eBooks
Committee for Economic Development , 1981
Buku Teks
Nevid, Jeffrey S.
Pearson Education International, 2008
Buku Teks