Zahra, A., Djamel, B. and Abdelmadjid, B. (2024) “Solutions of the equation d (kn) = ϕ (ϕ (n))”, Jordan Journal of Mathematics and Statistics, 17(3). Available at: https://jjms.yu.edu.jo/index.php/jjms/article/view/437 (Accessed: 3 April 2025).