Peter Sommerlad Guido Zgraggen Thomas Corbat Lukas Felber Retaining comments when refactoring code. 653-662 2008 OOPSLA Companion http://doi.acm.org/10.1145/1449814.1449817 conf/oopsla/2008c db/conf/oopsla/oopsla2008c.html#SommerladZCF08