[ 1] LEVINE N. Semi- open Sets and Semi- con tinui ty in Topological Spaces, Amer. [ J] . Math.Monthly, 1963, ( 10) : 36~ 41.[ 2] EL D N, HASANEIN I A, MASHOUR A S, NOIRI T. On P- reqular Spaces[ J] . Bull Math. de la Soc. Sci. Math. de ha R. S. deRoumanie Tome 27, 1983, ( 4) : 311~ 315.[ 3] NJASTAD O. On Some Classes of Nearly Open Sets[ J] . Pacific Jour. Math. , 1965, 15( 3) : 961~ 970.
