• Matrix Transforms Into the Speed-Maddox Spaces Over Ultrametric Fields IINatarajan, Pinnangudi Narayanasubramanian; Aasma, AntsPublications de l Institut Mathematique2025 / p. 89-96 https://doi.org/10.2298/PIM2532089N http://elib.mi.sanu.ac.rs/files/journals/publ/138/publn138p89-96.pdf
• Some Classes of Matrix Transformations between the Subsets of Maddox Spaces Defined by SpeedAasma, Ants; Natarajan, Pinnangudi NarayanasubramanianWSEAS transactions on systems2024 / p. 508-516 https://doi.org/10.37394/23202.2024.23.52 https://wseas.com/journals/systems/2024/b065102-034(2024).pdf https://www.scopus.com/sourceid/144813 https://www.scopus.com/pages/publications/86000153816?inward