[1] J. Ježek:
The lattice of equational theories. Part I: Modular elements. Czech. Math. J. 31 (1981), 127-153.
MR 0604120
[2] J. Ježek:
The lattice of equational theories. Part II: The lattice of full sets of terms. Czech. Math. J. 31 (1981), 573-603.
MR 0631604
[3] J. Ježek:
The lattice of equational theories. Part III: Definability and automorphisms. Czech. Math. J. 32 (1982), 129-164.
MR 0646718