Beth's and Craig's properties via epimorphisms and amalgamation in algebraic logic.

Ildikó Sain Beth's and Craig's properties via epimorphisms and amalgamation in algebraic logic. 209-225 1988 conf/aluacs/1988 Algebraic Logic and Universal Algebra in Computer Science db/conf/aluacs/aluacs1988.html#Sain88 http://dx.doi.org/10.1007/BFb0043086