HERSH, Marion A. Assistive Technology for Visually Impared and Blind People / Marion A. Hersh and Michael A. Johnson - London , Springer Verlag London Limited , c2008 - xxvii, 725p . : ill . ; Include References and Index ISBN: 9781846288661 Subjects--Topical Terms: Assistive Technology Dewey Class. No.: 362.41 HER