WASET
    Liu Shu and  Dong Shangjia,  Combine Duration and "Select the Priority Trip" to Improve the Number of Boats.   journal   = {International Journal of Environmental and Ecological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    December 2012, vol. 72(12). 744 - 748
    [viewed 11 May 2024]. Available from: https://publications.waset.org/pdf/14589.