Manisha Chaudhary and  Joydip Dhar and  Govind Prasad Sahu,  Mathematical Model of Depletion of Forestry Resource: Effect of Synthetic Based Industries.   journal   = {International Journal of Biological and Ecological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    September 2013, vol. 76(4). 639 - 643
    [viewed 30 March 2020]. Available from: https://publications.waset.org/pdf/16903.