Inventories (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary of inventories
Trade goods	$ 111,461	$ 55,689
Advances given for purchases	0	0
Total	$ 111,461	$ 55,689	$ 365,643	$ 259,883