Ask HN: Recommended books for a sales newbie?

We're about to launch our first freemium based web app and will primarily be advertising the service via traditional online channels (organic search, adwords, banners etc) in order to generate online sales. Our application is aimed at marketing agencies, project teams and social media power users and can be used online, or the source code downloaded to work within corporate firewalls.

Although sufficiently experienced at marketing online, we don't really have any experience selling offline (face to face, conferences, cold-calls, events etc). Being based in London, it seems sensible to try and obtain sales offline as a lot of our UK target market will be based here, particularly at events and conferences.

We already have two other relatively successful websites, but have relied on our ad networks (not Google) to provide the sales expertise - our new project does not display banner ads, so this is not an option.

As with any startup, time is very very precious, so i'm looking to source a couple of powerful, practical sales books that don't take months to read or require weeks to learn a completely new vocabulary.

I've been searching around HN for recommendations, and have so far picked our the following books that have been suggested (i've already read The Secrets of Selling by Geoff King)

* Jeffrey Gitomer's Little Red Book of Selling * How I Raised Myself from Failure to Success in Selling - by Frank Bettger * Bag the Elephant - by Steve Kaplan

Are there any other books that you would recommend for a small startup in our situation? Any help you can offer would be appreciated.