1. Abbott, J.C.: Implicational algebras. Bull. Math. Soc. Sci. Math. R. S. Roumanie 11, 3–23 (1967)
2. Aglianò P., Ferreirim I.M.A., Montagna, F.: Basic hoops: an algebraic study of continuous t-norms. draft (2000)
3. Bergman, C.: Universal Algebra. Pure and Applied Mathematics, CRC Press, Chapman & Hall, Fundamental and Selected Topics (2012)
4. Blok, W.J., Ferreirim, I.M.A.: On the structure of hoops. Algebr. Universalis 43, 233–257 (2000)
5. Blok, W.J., Ferreirim, I.M.A.: Hoops and their implicational reducts (abstract). Algebraic Methods in Logic and Computer Science. Banach Center Publications 28, 219–230 (1993)