1. R. Engelking, General Topology (Heldermann-Verlag, Berlin, 1989).
2. J. Fell, Proc. Amer. Math. Soc. 13, 472 (1962).
3. H. Attouch, Variational Convergence for Functions and Operators (Pitman, Boston, MA, 1984).
4. G. Matheron, Random Sets and Integral Geometry (Wiley, New York, 1975).
5. D. A. Podoprikhin and T. N. Fomenko, Math. Notes 106 (4), 591 (2019).