WASET
    José Paulo Leal and  Ricardo Queirós,  Defining Programming Problems as Learning Objects.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    October 2009, vol. 34(10). 2361 - 2368
    [viewed 29 March 2024]. Available from: https://publications.waset.org/pdf/2892.