@article{oai:tsukuba.repo.nii.ac.jp:00015774,
author = {Ochiai, Shoji},
issue = {1},
journal = {Tsukuba journal of mathematics},
month = {Jun},
note = {Let T(n) be the number of topologies on a set with n-element. It is an old and difficult problem to determine this number. Many authors attacked this problem and so far determined this number T(n) for small value n. ...},
pages = {63--74},
title = {On a topological invariant of finite topological spaces and enumerations},
volume = {16},
year = {1992}
}