Perun, H. M., and V. K. Yasinsky. “Investigation of the Cauchy Problem for Stochastic Partial Differential Equations”.
Ukrains’kyi Matematychnyi Zhurnal, vol. 45, no. 9, Sept. 1993, pp. 1259–1265,
https://umj.imath.kiev.ua/index.php/umj/article/view/5928.