1. Adámek, J., El Bashir, R., Sobral, M., Velebil, J.: On functors that are lax epimorphisms. Theory Appl. Categ. 8.20, 509–521 (2001)
2. LNCS;A. Balan,2011
3. Baltag, A.: A logic for coalgebraic simulation. Electron. Notes Theor. Comput. Sci. 33, 41–60 (2000)
4. Lecture Notes in Mathematics;M. Barr,1970
5. El Bashir, R., Velebil, J.: Reflective and coreflective subcategories of presheaves. Theory Appl. Categ. 10.16, 410–423 (2002)