VareniukN. A., GalbaE. F., SergienkoI. V., and KhimichA. N. 2018. “Weighted pseudoinversion with Indefinite Weights”. Ukrains’kyi Matematychnyi Zhurnal 70 (6), 752-72. https://umj.imath.kiev.ua/index.php/umj/article/view/1593.