Actually yeah.
Cameron S. Foote "The Creative Business Guide to Running a Graphic Design Business"
Ya might wanna pick up
Tad Crawford and Eva Doman Bruck "Business and Legal Forms for Graphic Designers"
Thats a good one cuz it goes through negotiation check lists. After reading some of this material ya might see the light that Adult Design is really not worth your time. I have a few good adult clients but there are better industries out there willing to pay what your worth and not go on the "cheap"
The few Adult companies out there willing to pay your worth are few and far between. Ya would think with all the said money that flies around this business ya would not have to be scrambling with em over $20.00 banners.
Pitch them bottom feeders and raise your prices if you must.