S. A. Polin and H. Ahsan, “Three-dimensional Manifolds as Slices of Infinite-dimensional Hilbert Manifolds: A Geometric Model of the Universe: Three-dimensional Manifolds as Slices of Infinite-dimensional Hilbert Manifolds”, Dhaka Univ. J. Sci., vol. 73, no. 2, pp. 187–195, Jul. 2025.