Matsak, I. K., and A. M. Plichko. 1993. “On the Law of the Iterated Logarithm for Weighted Sums of Independent Random Variables in a Banach Space”. Ukrains’kyi Matematychnyi Zhurnal 45 (9): 1225–1231. https://umj.imath.kiev.ua/index.php/umj/article/view/5924.