edited by Valters Nollendorfs and Karl F. Markgraf
German Academic Exchange Service, 1986
Buku Referensi
Frederick A. Praeger, 1966
Buku Teks
Rand McNally, [date of publication not identified]
Buku Referensi
Wozniak, Chris A., editor
[, Springer], 2012
eBooks
Petrides, George A.
Houghton Mifflin, 1988
Buku Teks