1. Barraga NC, Morris JE (1980) Program to develop efficiency in visual functioning. Sourcebook on low vision. American Printing House, Louisville
2. Bentzen BL, Martin JR (2010) Teaching the use of orientation aids for orientation and mobility. In: Foundations for orientation and mobility. AFB, New York
3. Blasch BB, Long RG, Griffin-Shirly N (1989) Results of a national survey of electronic travel aid use. J Vis Impair Blindness 83
4. Blasch BB, Wiener WR, Welshe RL (1997) Foundations of orientation and mobility, 2nd edn. AFB Press, New York
5. Campbell AJ, Roberston MC, LaGrow SJ et al (2005) Randomized controlled trial of prevention of falls in people aged >75 with severe visual impairment: the VIP trial. BMJ 331:817–820