[1] M. Abad, J.M. Cornejo and J.P. Diaz Varela, The variety of semi-Heyting algebras
satisfying the equation , Reports on Mathematical Logic
46 (2011), 75-90.
[2] M. Abad, J.M. Cornejo and J.P. Daz Varela, The variety generated by semi-Heyting
chains, Soft Computing 15 (2011), 721-728.
[3] M. Abad and L. Monteiro, Free symmetric Boolean algebras, Revista de la U.M.A.
27 (1976), 207-215.
[4] R. Balbes and PH. Dwinger, Distributive Lattices", Univ. of Missouri Press,
Columbia, 1974.
[5] S. Burris and H.P. Sankappanavar, A Course in Universal Algebra", Springer-
Verlag, New York, 1981. The free, corrected version (2012) is available online as a
PDF file at math.uwaterloo.ca/fisnburris.
[6] G. Gratzer, Lattice Theory", W.H.Freeman and Co., San Francisco, 1971.
[7] A. Horn, Logic with truth values in a linearly ordered Heyting algebras, J. Symbolic.
Logic 34 (1969), 395-408.
[8] B. Jhonsson, Algebras whose congruence lattices are distributive, Math. Scand. 21
(1967), 110-121.
[9] V.Yu. Meskhi, A discriminator variety of Heyting algebras with involution, Algebra
i Logika 21 (1982), 537-552.
[10] A. Monteiro, Sur les algebres de Heyting symetriques, Portugaliae Mathemaica 39
(1980), 1-237.
[11] W. McCune, Prover9 and Mace 4, http://www.cs.unm.edu/mccune/prover9/.
[12] H. Rasiowa, An Algebraic Approach to Non-Classical Logics", North{Holland
Publ.Comp., Amsterdam, 1974.
[13] H. Rasiowa and R. Sikorski, The Mathematics of Metamathematics", Warsazawa,
1970.
[14] H.P. Sankappanavar, Heyting algebras with dual pseudocomplementation, Pacific J.
Math. 117 (1985), 405-415.
[15] H.P. Sankappanavar, Pseudocomplemented Okham and De Morgan algebras,
Zeitschr. f. math. Logik und Grundlagen d. Math. 32 (1986), 385-394.
[16] H.P. Sankappanavar, Heyting algebras with a dual lattice endomorphism, Zeitschr.
f. math. Logik und Grundlagen d. Math. 33 (1987), 565{573.
[17] H.P. Sankappanavar, Semi-De Morgan algebras, J. Symbolic. Logic 52 (1987), 712-
724.
[18] H.P. Sankappanavar, Semi-Heyting algebras: An abstraction from Heyting algebras,
Actas del IX Congreso Dr. A. Monteiro (2007), 33-66.
[19] H.P. Sankappanavar, Semi-Heyting algebras II. In Preparation.
[20] H.P. Sankappanavar, Expansions of semi-Heyting algebras. I: Discriminator varieties,
Studia Logica 98 (1-2) (2011), 27-81.
[21] H.P. Sankappanavar, Expansions of semi-Heyting algebras. II. In Preparation.
[22] J, Varlet, A regular variety of type h2; 2; 1; 1; 0; 0i, Algebra Universalis 2 (1972),
218-223.
[23] H. Werner, Discriminator Algebras", Studien zur Algebra und ihre Anwendungen,
Band 6, Academie{Verlag, Berlin, 1978.