KukushA. G. “Asymptotic Normality of a Projective Estimator of an Infinite-Dimensional Parameter of Nonlinear Regression”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 45, no. 9, Sept. 1993, pp. 1205–1214, https://umj.imath.kiev.ua/index.php/umj/article/view/5922.