Jung–Min Yang,  Conditions for Model Matching of Switched Asynchronous Sequential Machines with Output Feedback.   journal   = {International Journal of Electrical and Computer Engineering}, [online]. World Academy of Science, Engineering and Technology.
    November 2017, vol. 121(1). 55 - 59
    [viewed 23 January 2022]. Available from: https://publications.waset.org/pdf/10006124.