1. Andréka, H., Németi, I., Sain, I.: Algebraic logic. In: Handbook of Philosophical Logic, 2nd edn., vol. 2. Kluwer Academic Publishers, Dordrecht (2001)
2. Birkhoff, G.: Lattice Theory. AMS Colloquium Publications (1967)
3. Blackburn, P., Rijke, M.: Why combine logics? Studia Logica 59(1), 5–27 (1997)
4. Blok, W., Pigozzi, D.: Algebraizable Logics, vol. 77. Memoires AMS (1989)
5. Caleiro, C.: Combining Logics. PhD thesis, Universidade Técnica de Lisboa (2000)