WASET
    Ping Liu and  Yongkun Li,  Analysis of Permanence and Extinction of Enterprise Cluster Based On Ecology Theory.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    August 2011, vol. 56(8). 1305 - 1310
    [viewed 24 April 2024]. Available from: https://publications.waset.org/pdf/5091.