The Workflow module
Getting started with the Workflow module
The Workflow widget
The Workflow module provides a configurable widget for changing the State of an entity.
Workflow & Actions, Triggers and Rules
Workflow provides actions, which can be used by the modules Trigger and Rules
Workflow on the web
These are some references, scripts, video's from the internet
Developer documentation for Workflow module
This is how you develop your own code for Workflow module.