books.google.co.uk - 1988 marked the first centenary of Recursion Theory, since Dedekind's 1888 paper on the nature of number. Now available in paperback, this book is both a comprehensive reference for the subject and a textbook starting from first principles.Among the subjects covered are: various equivalent approaches...http://books.google.co.uk/books/about/Classical_Recursion_Theory.html?id=ahBLqshTFMwC&q=elementarily+equivalent&utm_source=gb-gplus-shareClassical Recursion Theory
