Freese, Ralph S., 1946- Commutator theory for congruence modular varieties/ Ralph Freese, Ralph McKenzie. - Cambridge, UK: New York: Cambridge University Press, 1987. - 227 p.: ill.; 23 cm. - London Mathematical Society lecture note series; 125. . Includes indexes. Bibliography: p. [213]-220. ISBN: 0521348323 (pbk.) LCCN: 87011722 Nat. Bib. No.: GB87-22342 Subjects--Topical Terms: Algebra, Universal.Algebraic varieties.Congruence lattices. Dewey Class. No.: 512.24