Amerasinghe, Anthony Ranjit Bevis, author
Lake House Investments, 1971
Buku Teks
Trautz, F.M.
Munchen Muller 1926
Buku Teks
Arasartnam, Sinnappah, author
Prentice-Hall, 1964
Buku Teks
Bailey, Sydney D., author
William Brendon ans Son, 1952
Buku Teks
Walsh, Annmarie Hauck, author
MIT Press , 1978
Buku Teks