A practical examination of multimodal feedback and guidance signals for mobile touchscreen keyboards. - Tim Paek; Kenghao Chang; Itai Almog; Eric Badger; Tirthankar Sengupta (Mobile HCI, 2010)

Text Text Revolution: A Game That Improves Text Entry on Mobile Touchscreen Keyboards. - Dmitry Rudchenko; Tim Paek; Eric Badger (Pervasive, 2011)