Skorokhod A. V., and SlobodenyukN. Р. “On the Asymptotic Behaviour of Some Functionals of the Brownian Motion Process”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 18, no. 4, June 1966, pp. 60-71, https://umj.imath.kiev.ua/index.php/umj/article/view/8313.