WASET
    Rossitza M. Setchi and  Qiao Tang,  Concept Indexing using Ontology and Supervised Machine Learning .   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2007, vol. 1(1). 89 - 94
    [viewed 28 March 2024]. Available from: https://publications.waset.org/pdf/12208.