Burgschmidt, Ernst
Dortmund Lambert Lensing 1975
Buku Teks
Wade, Terence
New York : Oxford University Press, 2002
Buku Referensi
Donald Freeman and Jack C. Richardsand , author
Cambridge Cambridge University Press 1996
Buku Teks
Gowen, James A., author
McGraw-Hill, 1965
Buku Teks
Burgschmidt, Ernst
Dortmund Lambert Lensing 1975
Buku Teks