Wortman, Richard, author
Cambridge University Press, 1967
Buku Teks
Sorokin, G
Progress Publisher, 1967
Buku Teks
Willimott, Andy, author
Oxford University Press, 2017
eBooks
Sternberg, Fritz, author
The John Day, 1953
Buku Teks
Shteppa, Konstantin F., author
Rutgers University Press, 1962
Buku Teks