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2. The theory of commuting subalgebras of a complete Heyting algebra;Crants;Adv. in Math.,1998
3. Théorie algébrique des relations d'équivalence;Dubreil;J. Mathématiques,1939
4. The logic of commuting equivalence relations;Finberg,1996
5. The Theory of Linear Lattice;Haiman,1984