Nudel'man, A.A. (1994) “On M. G. Krein’s contribution to the moment problem”, Ukrains’kyi Matematychnyi Zhurnal, 46(1-2), pp. 63–75. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/5770 (Accessed: 5 December 2025).