* *[Quality practices and problems in free software projects](http://opensource.mit.edu/papers/michlmayr_hunt_probert-quality_practices_problems.pdf)* by Michlmayr, Hunt, Probert
* *[Rules and Tools for Software Evolution Planning and Management](http://www.springerlink.com/content/l4216085h77324q6/fulltext.pdf)* by Lehman and Ramil
* *[metrics and laws of software evolution - the nineties view](http://ieeexplore.ieee.org/iel3/5031/13795/00637156.pdf?tp=&arnumber=637156&isnumber=13795)* by Lehman and Ramil
+* *[Checking System Rules Using System-Specific, Programmer-Written Compiler Extensions](http://www.stanford.edu/~engler/mc-osdi.ps)* by Engler et al
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