P. G. Stegantseva and A. V. Skryabina, “Topologies on the $n$-element set that consistent with close to the discrete topologies on $(n −1)$-element set”, Ukr. Mat. Zhurn., vol. 73, no. 2, pp. 238–248, Feb. 2021, doi: 10.37863/umzh.v73i2.6174.