James, Elizebert, et al. “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”. Jurnal Pendidikan Bitara UPSI, vol. 15, June 2022, pp. 117-33, https://doi.org/10.37134/bitara.vol15.sp.12.2022.