http://finance.wharton.upenn.edu/~mrrobert/Teaching/LectureSlides/Class9_Leverage_Slides_Handout.pdf
http://www.12manage.com/methods_capm.html
http://www.quickmba.com/finance/cf/
http://www.12manage.com/methods_capm.html
http://pages.stern.nyu.edu/~adamodar/New_Home_Page/AppldCF/derivn/ch4deriv.html
http://pages.stern.nyu.edu/~adamodar/New_Home_Page/AppldCF/derivn/ch4deriv.html
These links has examples of unleveraging beta: