1. Resources, N.: NYC resources.
http://www.nyc.gov/html/dot/html/infrastructure/accessiblepedsignals.shtml
. Accessed 22 Apr 2018
2. APS: Accessible pedestrian signal features.
http://accessforblind.org/aps/aps-features/
. Accessed 22 Apr 2018
3. HAWK: Hawk pedestrian signal guide.
https://ddot.dc.gov/sites/default/files/dc/sites/ddot/publication/attachments/dc_hawk_pedestrian_signal_guide.pdf
. Accessed 22 June 2018
4. Crandall, W., Bentzen, B.L., Myers, L., Brabyn, J.: New orientation and accessibility option for persons with visual impairment: transportation applications for remote infrared audible signage. Clin. Exp. OPTOMETRY 84(3), 120–131 (2001)
5. Lookaround: Lookaround turorial.
https://getlookaround.com/
. Accessed 22 Apr 2018