Emerald Publishing Limited, 2019
eBooks
Dailey, Charles Alvin, 1923-, author
Parker, 1970
Buku Teks
Odiorne, George S., author
WED International, [Date of publication not identified]
Buku Teks
Hand, A.J., author
Popular Science, 1977.
Buku Teks
Davidson, George
Hodder and stoughton, 1989
Buku Teks