http://www.kenniffonline.com/profits-publishing/
I did some work in desktop publishing a nonprofit organization. I have not been paid. What I can do?
It makes no difference if they are for-profit or not for profit, has a contract that is enforceable. try the sweet way first, tell them I understand, but we need your money .. What Measurements can be made that both can live with, otherwise the file in small claims court .. easy and fast!
Guide to Book Publishing Profits