Gospel Music Techniques
If you are unfamiliar with his name, just know that the Rudy Atwood style of playing is largely what has framed our concept of what the Evangelistic style is supposed to be. Rudy Atwood was a preacher as well as a pianist, and stressed classical training as well as improvisation. All his arrangments contain sweeping octave runs in both the right and left hands, as well as full, majestic chord accompaniments.
It's very difficult to find any of Mr. Atwood's books or videos. I have found a few of them on eBay (don't bid against me), but even that is a rare occurrence, and the price always goes high. They are largely hard to come by, so buy them when you can.