http://www.tutorialspoint.com/makefile/why_makefile.htm
http://www.jfranken.de/homepages/johannes/vortraege/make_inhalt.en.html
http://www.gnu.org/software/make/manual/make.html
%: http://www.gnu.org/software/make/manual/make.html#Pattern-Intro
Advanced: http://www.cprogramming.com/tutorial/makefiles_continued.html
Makefile tutorial