books.google.com.au - This book is an introduction to the Schwinger action principle in quantum mechanics and quantum field theory, with applications to a variety of different models including Bose-Einstein condensation, the Casimir effect, and trapped Fermi gases. The book begins with a brief review of the action principle...http://books.google.com.au/books/about/The_Schwinger_Action_Principle_and_Effec.html?id=krF8Z77vq3cC&q=renormalization&utm_source=gb-gplus-shareThe Schwinger Action Principle and Effective Action
