WASET
    Kashif Laeeq and  Zubair A. Shaikh,  Challenges and Opportunities of Cloud-Based E-Learning Systems.   journal   = {International Journal of Educational and Pedagogical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    March 2016, vol. 110(2). 693 - 697
    [viewed 24 April 2024]. Available from: https://publications.waset.org/pdf/10006858.