Florian Pfeffel and  Christoph A. Kexel and  Peter Kexel and  Maria Ratz ,  Characteristics of Football Spectators Using  Second Screen.   journal   = {International Journal of Economics and Management Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2016, vol. 116(8). 2747 - 2751
    [viewed 23 September 2024]. Available from: https://publications.waset.org/pdf/10005161.