Which book or dvd to get?

For kettle bell training, what should I get? A book or a DVD? And if so, which one? I’ve narrowed it down to The Russian Kettle Bell Challenge or Enter the Kettle Bell. I’ve had my Russian Red for almost a year, but am "home trained" ( youtube, dragondoor,etc.).I’d like to improve. And please don’t say get both book and dvd, let alone all 4. I just got a gift certificate, along with some good deals I’ve seen online ( the kettle bell itself was a gift). Maybe someday I’ll get all 4, but until then I can only get 1. Which 1? Any advice will be appreciated.