Like others have mentioned before, I like to reference several sources. I regularly use Hornady Handbook, Hodgdon #26, Modern Reloading by Richard Lee, The ABC's of Reloading by Dean Grennel, Loadmaps by Midway, and the One Book/One Caliber books. I also use information from the internet, but check them against my printed sources. Steve Ricciardelli's information is very good, and his website is very well done.