1. Birkhoff G.: Lattice Theory. Amer. Math. Soc. Colloq. Publ. vol. 25, rev. ed. Amer. Math. Soc., New York (1948)
2. Grätzer, G.: The Congruences of a Finite Lattice. A Proof-by-Picture Approach. Birkhäuser Boston (2006)
3. Grätzer G.: Lattice Theory: Foundation. Birkhäuser Verlag, Basel (2011)
4. Grätzer G., Lakser H., Schmidt E.T.: Congruence lattices of finite semimodular lattices. Canad Math. Bull. 41, 290–297 (1998)
5. Grätzer G., Schmidt E.T.: On inaccessible and minimal congruence relations. I. Acta Sci Math. (Szeged) 21, 337–342 (1960)