Hey Jeff,
I think Pops has written some great material over the years... any one of his books would be great. "How The Chops Work" is a really great resource.
The exercises I've been doing are simple and work on other things at the same time. I will do extremely slow / soft chromatic work from low F# to Double C and up (if I'm feelin' it that day). I also work on major scales, minor scales, modes, etc. 2 and 3 octaves. This helps keep the horn on my face for longer periods of time... I try to focus on "less" pressure and refocus the compression to my chops against the mouthpiece... not the mouthpiece being driven into my skull from pressure.
As goofy as this sounds, I also do another thing that Pops recommends (and so did Maynard) - I read flute music. You have to be comfortable with the register that you're playing in... otherwise nerves can take over.
K