1. http://www.scribd.com/doc/35189708/Kelimpahan-Unsur-Di-Alam
http://www.4shared.com/office/aeiqIrue/Kelimpahan_Unsur_Di_alam.html
http://www.google.co.id/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCUQFjA
B&url=http%3A%2F%2Fgintingryan.blogspot.com%2F2011%2F12%2Fkelimpahan-unsur-
di-
alam.html&ei=jtmYUNz9LcmPrgfciYCQCg&usg=AFQjCNGwtlYiFOul2jn0XYs3Zasym_I
1Tw
http://gintingryan.blogspot.com/2011/12/kelimpahan-unsur-di-alam.html
http://mancheslamic.blogspot.com/2011/05/kelimpahan-unsur-kimia-di-alam-semesta.html
http://id.wikipedia.org/wiki/Unsur_kimia
http://multimolten.wordpress.com/2011/04/19/reaksi-logam-alkali/
http://www.scribd.com/doc/45211132/Dampak-Dan-Manfaat-Unsur-Senyawa-Logam-Alkali;
https://www.google.co.id/#hl=id&biw=1024&bih=605&sclient=psy-
ab&q=kegunaan+logam+alkali&oq=kegunaan+lo&gs_l=hp.1.1.0l4.3033.7657.0.10490.11.6.
0.5.5.0.279.1465.2-
6.6.0...0.0...1c.1.L_A7i_q8dRg&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=b25ce254e686a83
4&bpcl=37189454