1. Johnstone P. T., Stone spaces, vol 3, Cambridge University Press, (1986). 2. Banaschewski B., Compactification of frames, Mathematische Nachrichten, 149 (1) (1990) 105-115. 3. Banaschewski B. and Mulvey C., Stone-Čech compactification of locales I, Houston Journal of Mathematics, 6 (3) (1980) 301-312. 4. Banaschewski B. and Mulvey C., Stone-Čech compactification of locales II, Journal of Pure and Applied Algebra, 33 (2) (1984) 107-122. 5. Banaschewski B. and Mulvey C. J., The Stone–Čech compactification of locales III, Journal of Pure and Applied Algebra, 185 (1) (2003) 25-33. 6. Banaschewski B., The real numbers in pointfree topology, Textos Mat, Sér B 12, (1997). 7. Estaji A., Karimi Feizabadi A., and Abedi M, Zero sets in pointfree topology and strongly z-ideals, Bulletin of the Iranian Mathematical Society, 41 (5) (2015) 1071-1084. 8. Picado J. and Pultr A., Frames and Locales: topology without points, Springer Science & Business Media, (2011). 9 . Gillman L. and Jerison M., Rings of continuous functions. Springer, (1976). 10. Ebrahimi M. M. and Mahmoudi M., Frame, Technical Report, Shahid Beheshti University, (1995). 11. Banaschewski B. and Gilmour C., Pseudocompactness and the cozero part of a frame, Commentationes Mathematicae Universitatis Carolinae , 37(1996) 577-588. 12. Azarpanah F., Karamzadeh O., and Aliabad A. R., On z◦-ideals in C (X), Fundamenta Mathematicae, 160 (1) (1999) 15-25. 13. Azarpanah F., On almost P-space, Far East J Math Sci Special, (2000) 121-132. 14. Dube T., Concerning P-frames, essential P-frames, and strongly zero-dimensional frames, Algebra universalis, 61 (1) (2009) 115-138.