Bakushinsky, A.B., M.Yu. Kokurin, and V.V. Kljuchev. 2006. “A Rate of Convergence and Error Estimates for Difference Methods Used to Approximate Solutions to Ill-Posed Cauchy Problems in a Banach Space”. Numerical Methods and Programming (Vychislitel’nye Metody I Programmirovanie) 7 (8):163-71. https://en.num-meth.ru/index.php/journal/article/view/204.