ZhdanovR. Z. “Integrability of Riccati Equations and Stationary Korteweg-De Vries Equations”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 51, no. 6, June 1999, pp. 856–860, https://umj.imath.kiev.ua/index.php/umj/article/view/4674.