1.http://www.goldfacts.org/en/supply_chain/refining/
2.http://www.investopedia.com/terms/t/trading-house.asp
3.http://www.google.com/images
4.http://www.dbmarketing.com/articles/Art216editorial.htm
5.http://www.goldbarsworldwide.com
6.http://money.howstuffworks.com/question213.htm
7.http://www.internationalresourcejournal.com/features/features_january_10/the_worldwide_gold_buying_boom.html