Djumabaev, N., and S.T. Qalekeeva. “TRIGONOMETRIYALÍQ TEŃLEMELERDI SHESHIWDE AYÍRÍM KORENLERDIŃ JOǴALÍP KETIW JAǴDAYLARÍN ANÍQLAW USÍLLARÍ”. SCIENCE and SOCIETY, no. 3-2, Sept. 2021, pp. 56-58, https://journal.ndpi.uz/ss/article/view/2021-3-2-027.