Xinli Zhang,  Nonoscillation Criteria for Nonlinear Delay Dynamic Systems on Time Scales.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    February 2014, vol. 85(1). 222 - 226
    [viewed 13 August 2022]. Available from: https://publications.waset.org/pdf/9997821.