Helen L. Bear, Gari Owen, Richard Harvey, Barry-John Theobald, "Some observations on computer lip-reading: moving from the dream to the reality," Proc. SPIE 9253, Optics and Photonics for Counterterrorism, Crime Fighting, and Defence X; and Optical Materials and Biomaterials in Security and Defence Systems Technology XI, 92530G (7 October 2014);