Welch, David, author
Heinemann, 1994
Buku Teks
Crosland, Anthony, 1918-, author
Macmillan, 1957
Buku Teks
Sinclair, William Angus
Robert Hale, 1955
Buku Teks
Von Mises, Ludwig, 1881-1973, author
Bradford and Dickens, 1953
Buku Teks
Agren, Maria, author
Oxford University Press, 2017
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