Zh.N. Tasmambetov, N. Rajabov, и Zh.K.Ubayeva. «THE COORDINATED SOLUTION OF TWO DIFFERENTIAL EQUATIONS IN PRIVATE DERIVATIVES OF THE THIRD ORDER». Известия НАН РК. Серия физико-математическая, вып. 4, август 2019 г., сс. 83-91, http://189185.vm7pq.group/physics-mathematics/article/view/1679.