Sharmila Karim and  Haslinda Ibrahim and  Zurni Omar,  New Scheme in Determining nth Order Diagrams for Cross Multiplication Method via Combinatorial Approach.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    June 2011, vol. 54(6). 920 - 923
    [viewed 22 May 2022]. Available from: https://publications.waset.org/pdf/12156.