http://www.research.att.com/sw/tools/graphviz/dotguide.pdf
http://www.research.att.com/sw/tools/graphviz/neatoguide.pdf
http://home.so-net.net.tw/oodtsen/wingraphviz/language/fontname.htm
http://home.so-net.net.tw/oodtsen/wingraphviz/language/fontname_shift_jis.htm
http://home.so-net.net.tw/oodtsen/wingraphviz/language/fontcolor.htm
http://home.so-net.net.tw/oodtsen/wingraphviz/language/colorname.htm
http://home.so-net.net.tw/oodtsen/wingraphviz/language/node_shape.htm
http://home.so-net.net.tw/oodtsen/wingraphviz/language/node_color.htm
http://home.so-net.net.tw/oodtsen/wingraphviz/language/arrow_type.htm
http://home.so-net.net.tw/oodtsen/wingraphviz/language/arrow_color.htm
http://seclab.cs.ucdavis.edu/~hoagland/Dot.html
