Bryson, Bill
Penguin Books, 1987
Buku Referensi
Kenyon, John Samuel
Merriam-Webster ; G. & C. Merriam Co., 1953
Buku Referensi
Jones, Daniel
Dent, 1940
Buku Referensi
Jones, Daniel
Cambridge University Press, 1992
Buku Referensi
Jones, Daniel
Cambridge University Press, 2003
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