Lawson, Robert B., author
Routledge & Francis Group, 2018
Buku Teks
Hertz, Frederick
Routledge & Kegan Paul Ltd., 1957
Buku Teks
Hertz, Frederick
Oxford University Press, 1944
Buku Teks
Richards, Graham, author
Routledge, 1997
Buku Teks
Leahey, Thomas Hardy, author
Prentice-Hall, 1997
Buku Teks