BogdanskiiY. V. “Cauchy Problem for the Essentially Infinite-Dimensional Heat Equation on a Surface in a Hilbert Space”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 47, no. 6, June 1995, pp. 737–746, https://umj.imath.kiev.ua/index.php/umj/article/view/5466.