Safitri Sembiring, Anggi, et al. “Analisis Harga Pokok Penjualan Dan Laba Kontribusi Terhadap Volume Penjualan Pada Perum Bulog Divre Sumut”. ILTIZAM Journal of Shariah Economics Research, vol. 7, no. 1, June 2023, pp. 109-23, https://doi.org/10.30631/iltizam.v7i1.1841.