1. Interval lattices and the amalgamation property;Berman, Joel;Algebra Universalis,1981
2. Idempotents in the groupoid of all 𝑆𝑃 classes of lattices;Day, Alan;Canad. Math. Bull.,1978
3. G. Grätzer, General lattice theory, Pure and Appl. Math. Series, Academic Press, New York; Mathematische Reihe, Band 52, Birkhäuser Verlag, Basel; Akademie Verlag, Berlin, 1978. (Russian translation: "MIR", Moscow, 1982.)
4. On a special type of subdirectly irreducible lattice with an application to products of varieties;Grätzer, George;C. R. Math. Rep. Acad. Sci. Canada,1980