PhonePoint pen: using mobile phones to write in air. - Sandip Agrawal; Ionut Constandache; Shravan Gaonkar; Romit Roy Choudhury (MobiHeld, 2009)

Using mobile phones to write in air. - Sandip Agrawal; Ionut Constandache; Shravan Gaonkar; Romit Roy Choudhury; Kevin Caves; Frank DeRuyter (MobiSys, 2011)