E. James, N. Mamat, and N. M. binti Mohd Radzi, “Implementation of ‘Spindle Box’ Activity in Improving the Understanding of Additional Operations for 4 Year Old Children: Pelaksanaan aktiviti ‘Spindle Box’ dalam Meningkatkan Kefahaman Operasi Tambah Terhadap Kanak-kanak 4 Tahun”, JPB, vol. 15, pp. 117–133, Jun. 2022, doi: 10.37134/bitara.vol15.sp.12.2022.