Montolalu, Chriestie. “Stability and Behaviour of Rotationally Symmetric Harmonic Maps From A Ball Into A Sphere”. d’Cartesian 5, no. 1 (April 29, 2016): 42–49. Accessed May 2, 2024. https://ejournal.unsrat.ac.id/v3/index.php/decartesian/article/view/12732.