Dawei Cai,  Earphone Style Wearable Device for Automatic Guidance Service with Position Sensing.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2017, vol. 121(1). 99 - 103
    [viewed 07 May 2024]. Available from: https://publications.waset.org/pdf/10006336.