Anam Ashraf and  Arif Raza,  Usability Issues of Smart Phone Applications: For Visually Challenged People.   journal   = {International Journal of Industrial and Manufacturing Engineering}, [online]. World Academy of Science, Engineering and Technology.
    April 2014, vol. 89(5). 760 - 767
    [viewed 25 May 2020]. Available from: https://publications.waset.org/pdf/9998241.