1. Adámek, J., Herrlich, H., Strecker, G.E.: Abstract and Concrete Categories. John Wiley & Sons, New York (1990)
2. Gierz, G., Hofmann, K.H., Keimel, K., et al.: A Compendium of Continuous Lattices. Springer, Berlin (1980)
3. Wei, H., Ming, L.Y.: Inverse limits in category of locales. Science in China (Ser. A) 41, 476–482 (1998)
4. Wei, H., Plewe, T.: Directed inverse limits of spatial locales. Proceedings of the American Mathematical Society 130, 2811–2814 (2002)
5. Hai-Yang, L., Sheng-Gang, L.: The inverse limits and direct limits in category of CoFrm. Journal of Northeast Normal University (Natural science edition) 38, 11–14 (2006) (in Chinese)