Link no, but what I know is what you should do is mix darker colors into lighter colors. When you mix you should slowly increase the % of the darker color until you get the color you want.
Once you get the color you want you may want to add a drying retarder. It increases the drying time, so you don't have to continously make more.
It has worked for me all this time, so I know this works. If you are looking for something more specific, I can try to look for a link. Hope this helps.