The android calulator was created by 

Spencer Owen - spuder.wordpress.com
Zach Pass
David Hixson
Chandler



It was created to demonstrate the power of the Application Controller Pattern. 

This pattern was origionally invented at Sun and was called the Enterprise Systems Pattern
It has been modified and simplified by Lee Barney, a professor at BYU Idaho
He has written multiple books and speaks at confrences worldwide explaining the power of this Pattern. 

Additional Information can be found in his books. 

The primary resouces lee barney's ebook which is under development
You can contact him and request a copy as this blog that he administers http://barneyooii.wordpress.com/course-information/syllabus/