If you have an iPad you can now get Richard Williams’ new Animator’s Survival Kit designed specifically for the mobile IOS. The book has been a standard in the animation field so it’s great to see this version which has interactive animation examples built into it. You can play each sample animation realtime or frame by frame, with or without onionskinning.
You can buy the full app or download a free version:
https://itunes.apple.com/us/app/the-animators-survival-kit/id627438690?mt=8