books.google.com - Algebraic theories, introduced as a concept in the 1960s, have been a fundamental step towards a categorical view of general algebra. Moreover, they have proved very useful in various areas of mathematics and computer science. This carefully developed book gives a systematic introduction to algebra based...http://books.google.com/books/about/Algebraic_Theories.html?id=siNlAn8Bm30C&q=Corollary&utm_source=gb-gplus-shareAlgebraic Theories