H. S. W. Nugroho, H. Handoyo, H. Prayitno, and A. Budiono, “Sort Elements Based on Priority, in order to Improve the Quality of E-Learning in Health Using Difficulty-Usefulness Pyramid with Weighting (DUP-We)”, Int. J. Emerg. Technol. Learn., vol. 14, no. 18, pp. pp. 186–193, Sep. 2019.