Recommended Reading The Ultimate Sales Letter, 4th Edition: Attract New Customers. Boost your Sales.by Dan S Kennedy Ogilvy On Advertising Paperbackby David Ogilvy Gary Halbert – The Gary Halbert Lettershttp://www.thegaryhalbertletter.com/newsletter-archives.htm CA$HVERTISING: How To Use More Than 100 Secrets Of Ad-Agency Psychology To Make Big Money Selling Anything To Anyoneby Drew Eric Whitman