Ethridge, Marcus E.
Wadsworth, 2010
Buku Teks SO
American Association for the Advancement of Science, 2018
Majalah, Jurnal, Buletin
Geoff Green, Ken Petford, Alan Short, David Walker
John Muray, 1975
Buku Referensi
Tillery, Bill W.
McGraw-Hill, 2013
Buku Teks SO
Derry, Gregory N.
Princeton University Press , 1999
Buku Teks SO