Baer, Werner
Richard D. Irwin, 1965
Buku Teks
Mendes, Marcos
Academic Press, 2015
eBooks
Skidmore, Thomas E.
Oxford University press, 2007
Buku Teks
Baer, Werner
Frederick A. Praeger, 1995
Buku Teks
Singapore UniVersity Press for ISEAS, 1975
Buku Teks