Can someone direct me to a tutorial of drawing wrinkles in the face?

I am drawing a portrait but I am having trouble shading the wrinkles. Can anyone direct me to a tutorial of this?Can someone direct me to a tutorial of drawing wrinkles in the face?
The best book for drawing is


';Drawing with the right side of your brain';





Check out the site:


http://www.drawright.com/





good luckCan someone direct me to a tutorial of drawing wrinkles in the face?
http://www.morecoloringpages.com


Have a look on this website, it has ';How to draw images'; section. This may help you !

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