hi.....

for calcium

http://www.ajcn.org/content/83/6/1444.full

http://www.nlm.nih.gov/medlineplus/ency/article/002412.htm

http://www.lenntech.com/periodic/elements/ca.htm

http://essentialvitaminsguide.com/41/calcium-and-the-human-body/

http://www.organicfacts.net/health-benefits/minerals/health-benefits-of-calcium.html

for iron

http://www.healthy-vitamin-choice.com/iron.html

http://www.organicfacts.net/health-benefits/minerals/health-benefits-of-iron.html

http://wiki.answers.com/Q/Effects_of_too_much_iron_on_human_health

http://www.lenntech.com/periodic/elements/fe.htm

http://www.healthvitaminsguide.com/minerals/iron.htm

for magnesium

http://www.healthy.net/scr/article.aspx?Id=541

http://www.mgwater.com/

http://www.afibbers.org/magnesium.htm

http://www.ctds.info/5_13_magnesium.html

http://www.mg12.info/

for silica

http://www.drpasswater.com/nutrition_library/Dirk_Vanden_Berghe.html

http://www.ncbi.nlm.nih.gov/pubmed/17435951

http://www.chiff.com/vitamins/silicon.htm

http://www.lenntech.com/periodic/elements/si.htm

http://www.holisticwebs.com/cancer/silica.pdf

for boron

http://www.hbci.com/~wenonah/hydro/b.htm

http://www.acu-cell.com/b.html

http://www.lenntech.com/periodic/elements/b.htm

http://www.raysahelian.com/boron.html

http://www.healingwithnutrition.com/mineral.html

http://www.jctonic.com/include/minerals/boron.htm

http://www.tandurust.com/health-faq-5/boron-deficiency.html