References
- Algebra Univ. v.15 On the structure of varieties with equationally definable principal congruences I Block, W.J.;Pigozzi, D.
- Algebra Univ. v.18 On the structure of varieties with equationally definable principal congruences II Block, W.J.;Kohler, P.;Pigozzi, D.
- Kobe J. Mathem. v.2 A note on deductive systems of a Hilbert algebra Buseneag, D.
- Collection de Logique Mathematique, Series A v.21 Sur les algebres de Hilbert Diego, A.
- Math. Japon. v.43 Deductive systems of Hilbert algebras Jun, Y.B.