Fazekas, L., A. G. Kukush, and S. Zwanzig. 2004. “Correction of Nonlinear Orthogonal Regression Estimator”. Ukrains’kyi Matematychnyi Zhurnal 56 (8), 1101–1118. https://umj.imath.kiev.ua/index.php/umj/article/view/3825.