Program: UML

http://stackoverflow.com/questions/15376/whats-the-best-uml-diagramming-tool

http://en.wikipedia.org/wiki/List_of_UML_tools

Python: Can dependency injection prevent a circular dependency?

Can dependency injection prevent a circular dependency?
http://stackoverflow.com/questions/2053044/can-dependency-injection-prevent-a-circular-dependency

http://stackoverflow.com/questions/5672308/avoid-circular-references-with-services-and-di

http://stackoverflow.com/questions/2053044/can-dependency-injection-prevent-a-circular-dependency

http://stackoverflow.com/questions/2608875/bad-design-constructor-of-composition-uses-this

http://www.potstuck.com/2009/01/08/php-dependency-injection/

Single Responsibility Principle
http://en.wikipedia.org/wiki/Single_responsibility_principle

Python: Decorator

Decorators I: Introduction to Python Decorators
http://www.artima.com/weblogs/viewpost.jsp?thread=240808

Decorators II: Introduction to Python Decorators
http://www.artima.com/weblogs/viewpost.jsp?thread=240845