Zafar Madat o’g’li Murtozaqulov. “KOMBINATORIKAGA DOIR MASALALARINI YECHISHDA FORMULALARNI TO’G’RI QO’LLASH”. Uzbek Scholar Journal, vol. 9, Oct. 2022, pp. 272-7, https://uzbekscholar.com/index.php/uzs/article/view/320.