American Association for the Advancement of Science, 2018
Majalah, Jurnal, Buletin
Tillery, Bill W.
McGraw-Hill, 2013
Buku Teks
Geoff Green, Ken Petford, Alan Short, David Walker
John Muray, 1975
Buku Referensi
Butterfield, Herbert
The Free Press , 1957
Buku Teks
Pomeroy, John H.
Holt, Rinehart and Winston, 1964
Buku Teks