http://www.javacodegeeks.com/2014/06/code-for-maintainability-so-the-next-developer-doesnt-hate-you.html
http://www.cs.vu.nl/csmr2007/workshops/SQM07_paper3.pdf
http://lesscode.org/2005/12/30/maintainable-programmers/
http://cleancode.sourceforge.net/wwwdoc/maintainability.html