WASET
    P. Nazemzadeh and  A. Dideban and  M. Zareiee,  Fail-safe Modeling of Discrete Event Systems using Petri Nets.   journal   = {International Journal of Electrical and Computer Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2011, vol. 49(1). 24 - 29
    [viewed 19 April 2024]. Available from: https://publications.waset.org/pdf/8187.