WASET
    Wuthichai Wongthatsanekorn,  A Goal Programming Approach for Plastic Recycling System in Thailand.   journal   = {International Journal of Industrial and Manufacturing Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2009, vol. 25(1). 23 - 28
    [viewed 29 March 2024]. Available from: https://publications.waset.org/pdf/5035.