1. Bergman G.M.: Hereditary commutative rings and centres of hereditary rings. Proc. Lond. Math. Soc. 23(3), 214–236 (1971)
2. Comer S.D.: Elementary properties of structures of sections. Bol. Soc. Mat. Mexicana (2) 19(2), 78–85 (1974)
3. Feferman S., Vaught R.L.: The first order properties of products of algebraic systems. Fund. Math. 47, 57–103 (1959)
4. Hodges W.: Model Theory, Encyclopedia of Mathematics and its Applications, vol. 42. Cambridge University Press, Cambridge (1993)
5. Koppelberg, S.: Handbook of Boolean algebras, vol. 1. In: Donald Monk J., Bonnet R. (eds.) North-Holland Publishing Co., Amsterdam (1989)