1. Aliabad, A.R., Azarpanah, F., Paimann: $$z$$-ideals and $$z^\circ $$-ideals in the factor rings of $$C(X)$$. Bull. Iran. Math. Soc. 36(1), 211–226 (2010)
2. Aliabad, A.R., Mohamadian, R.: On $$sz^\circ $$-ideals in polynomial rings. Commun. Algebra 39, 701–717 (2011)
3. Aliabad, A.R., Mohamadian, R.: On $$z$$-ideals and $$z^\circ $$-ideals of power series rings. J. Math. Extens. 7(2), 93–108 (2013)
4. Atiyah, M.F., Macdonald, I.G.: Introduction to Commutative Algebra. Addison-Wesely, Reading (1969)
5. Azarpanah, F., Mohamadian, R.: $$\sqrt{z}$$-ideals and $$\sqrt{z^\circ }$$-ideals. Acta. Math. Sin. 23(6), 989–996 (2007)