1. Ajayi SO, Oladipo MOA, Ogunsuyi HO, Adebayo AO (2002) Determination of the minor and trace elements in Biriniwa tin pyrite and ornamental lead/zinc ore using neutron activation analysis. Bull Chem Soc Ethiopia, 16(2):207-211 ( http://pi2.ingenta.com/content/cse/bcse/2002/00000016/00000002/art00011;jsessionid=vj00mwu3ct8h.alice )
2. Alloway BJ (1995) The origins of heavy metals in soils. In: Alloway BJ (ed) Heavy metals in soil, 2nd edn. Blackie Academic and Professional, London, pp 38–57
3. ATSDR (Agency for Toxic Substances and Disease Registry) (1990a) Toxicological profile for copper. Prepared by syracuse research corporation for ATSDR, U.S. public health service under Contract 88-0608-2. ATSDR/TP-90-08
4. Bangha E, Elsner P, Kistler GS (1997) Supression of UV induced erythema by tropical treatment with melatonin (n-acetyl-5-methlyoxytryptamine). Influence of the application time point. Dermatology 195(3):248–252
5. ACSB (The ASEAN Cosmetic Scientific Body) (2007) The report of the eighth meeting of the ASEAN consultative committee for standards and quality (ACCSQ) held in Ho Chi Minh City, Viet Nam on 10–11 December 2007. ( http://www.bfad.gov.ph/ACCSQ%20COSMETIC/ASEAN%20Cosmetic%20Meeting_PDF/ANNEX%2010%208th%20ACSB%20Meeting%20report%20-%20Final.pdf )