The following resources were both instrumental in compiling the information you can find on this website as well as being excellent resources for collectors wishing to advance their knowledge of Trade Dollars.
http://en.wikipedia.org/wiki/Trade_dollar
http://en.wikipedia.org/wiki/Trade_Dollar_(United_States_coin)
http://www.tradedollarnut.com/Home%20Page/Home%20first%20links/Collecting/Collecting.htm
http://reviews.ebay.com/Fake-U-S-Trade-dollars_W0QQugidZ10000000000049445
http://www.coinfacts.com/silver_dollars/trade_dollars/trade_dollars.html
http://www.pcgs.com/prices/PriceGuideDetail.aspx?c=743&title=Trade+Dollar
http://www.collectorusa.com/articles/tradedollar.php
http://www.coin-newbies.com/articles/trade_dollar.html
http://www.tulving.com/$1trade.html
http://www.numismedia.com/fmv/prices/trddlr/pricesgd.shtml
http://www.us-coin-values-advisor.com/US-Trade-Dollars.html
http://www.amazon.com/Buyers-Silver-Dollars-United-States/dp/0974237175
http://www.amazon.com/Silver-Dollars-Trade-United-States/dp/0943161487
http://www.numismaticenquirer.com/TNE/Counterfeit%20Trade%20Dollars.html
http://www.coinworld.com/news/102802/news-3.asp
http://www.google.com/url?sa=U&start=38&q=http://books.google.com/books%3Fhl%3Den%26id%3DonRjLfCcdVIC%26dq%3Dtrade%2Bdollars%26printsec%3Dfrontcover%26source%3Dweb%26ots%3Dgce8YwCMtz%26sig%3DxudMV0xzZS-H12fZCN0k9lX8SvA&usg=AFQjCNGWmDA5ZXS_eWpSs0YsPuJVfTFveQ&oi=book_result&resnum=8&ct=result