1. The best book I've read on sales is:

"How I Raised Myself from Failure to Success in Selling"(1952) by Frank Bettger

2. Everything at Heavybit is excellent,

their sales videos are very nice:

http://www.heavybit.com/library/developer-sales

And an must see video for me was:

http://www.heavybit.com/library/video/2015-05-12-jason-lemki...